This page documents an English Wikipedia content guideline. Editors should generally follow it, though exceptions may apply. Substantive edits to this page should reflect consensus. When in doubt, discuss first on this guideline's talk page. |
This page in a nutshell: Cite reliable sources. You can add a citation by selecting from the drop-down menu at the top of the editing box. In markup, you can add a citation manually using ref tags. More elaborate and useful ways to cite sources are detailed below. |
Are you new here? Welcome! There is a simplified version of this page at Help:Referencing for beginners. |
A citation, or reference, uniquely identifies a source of information, e.g.:
Wikipedia's verifiability policy requires inline citations for any material challenged or likely to be challenged, and for all quotations, anywhere in article space.
A citation or reference in an article usually has two parts. In the first part, each section of text that is either based on, or quoted from, an outside source is marked as such with an inline citation. This is usually displayed as a superscript footnote number: The second necessary part of the citation or reference is the list of full references, which provides complete, formatted detail about the source, so that anyone reading the article can find it and verify it.
This page explains how to place and format both parts of the citation. Each article should use one citation method or style throughout. If an article already has citations, preserve consistency by using that method or seek consensus on the talk page before changing it Help:Referencing for beginners", for a brief introduction on how to put references in Wikipedia articles; and cite templates in Visual Editor, about a graphical way for citation, included in Wikipedia.
. While you should try to write citations correctly, what matters most is that you provide enough information to identify the source. Others will improve the formatting if needed. See: "<ref>Rawls 1971, p. 1.</ref>
, which renders as Rawls 1971, p. 1.. These are used together with full citations, which are listed in a separate "References" section or provided in an earlier footnote.Forms of short citations used include author-date referencing (APA style, Harvard style, or Chicago style), and author-title or author-page referencing (MLA style or Chicago style). As before, the list of footnotes is automatically generated in a "Notes" or "Footnotes" section, which immediately precedes the "References" section containing the full citations to the source. Short citations can be written manually, or by using either the {{sfn}}
or {{harvnb}}
templates or the {{r}}
referencing template. (Note that templates should not be added without consensus to an article that already uses a consistent referencing style.) The short citations and full citations may be linked so that the reader can click on the short note to find full information about the source. See the template documentation for details and solutions to common problems. For variations with and without templates, see wikilinks to full references. For a set of realistic examples, see these.
This is how short citations look in the edit box:
The Sun is pretty big,<ref>Miller 2005, p. 23.</ref> but the Moon is not so big.<ref>Brown 2006, p. 46.</ref> The Sun is also quite hot.<ref>Miller 2005, p. 34.</ref>
== Notes ==
{{reflist}}
== References ==
* Brown, Rebecca (2006). "Size of the Moon", ''Scientific American'', 51 (78).
* Miller, Edward (2005). ''The Sun''. Academic Press.
This is how they look in the article:
The Sun is pretty big, but the Moon is not so big. The Sun is also quite hot.
Notes
References
Shortened notes using titles rather than publication dates would look like this in the article:
When using manual links it is easy to introduce errors such as duplicate anchors and unused references. The script User:Trappist the monk/HarvErrors will show many related errors. Duplicate anchors may be found by using the W3C Markup Validation Service.
By citing sources for Wikipedia content you enable users to verify that the cited information is supported by reliable sources – improving the credibility of Wikipedia while showing that the content is not original research. You also help users find additional information on the subject; and by giving attribution you avoid plagiarising the source of your words or ideas.
In particular, sources are needed for material that is challenged or likely to be challenged. If reliable sources cannot be found for challenged material, it is likely to be removed from the article. Sources are also required when quoting someone, with or without quotation marks, or closely paraphrasing a source. But the need to cite sources is not limited to those situations: editors are always encouraged to add or improve citations for any information in an article.
Citations are especially desirable for statements about living persons, particularly when the statements are contentious or potentially defamatory. In accordance with the biography of living persons policy, unsourced information of this type is likely to be removed on sight.
For an image or other media file, details of its origin and copyright status should appear on its file page. Image captions should be referenced as appropriate just like any other part of the article. A citation is not needed for descriptions such as alt text that are verifiable directly from the image itself, or for text that merely identifies a source (e.g., the caption "Belshazzar's Feast (1635)" for File:Rembrandt-Belsazar.jpg).
Citations are not used on disambiguation pages (sourcing for the information given there should be done in the target articles). Citations are often omitted from the lead section of an article, insofar as the lead summarizes information for which sources are given later in the article, although quotations and controversial statements, particularly if about living persons, should be supported by citations even in the lead. See WP:LEADCITE for more information.
Per WP:PAIC, citations should be placed at the end of the text that they support. Material that is repeated multiple times in a paragraph does not require an inline citation for every mention. If you say an elephant is a mammal more than once, provide one only at the first instance. Avoid cluttering text with redundant citations like this:
Elephants are large land mammals ... Elephants' teeth are very different from those of most other mammals. Unlike most mammals, which grow baby teeth and then replace them with a permanent set of adult teeth, elephants have cycles of tooth rotation throughout their entire lives.
This does not apply to lists or tables, nor does it apply when multiple sources support different parts of a paragraph or passage. Citation requirements for WP:DYK may require a citation to be inserted (for the duration of the DYK listing) even within a passage completely cited to the same sources.
Inline citations allow the reader to associate a given piece of material in an article with the specific reliable source(s) that support it. Inline citations are added using footnotes, long or short.
To create a footnote, use the <ref>...</ref>
syntax at the appropriate place in the article text, for example:
Justice is a human invention.<ref>Rawls, John. ''A Theory of Justice''. Harvard University Press, 1971, p. 1.</ref> It ...
which will be displayed as something like:
It will also be necessary to generate the list of footnotes (where the citation text is actually displayed); for this, see the previous section.
As in the above example, citation markers are normally placed after adjacent punctuation such as periods (full stops) and commas. For exceptions, see the WP:Manual of Style § Punctuation and footnotes. Note also that no space is added before the citation marker. Citations should not be placed within, or on the same line as, section headings.
The citation should be added close to the material it supports, offering text–source integrity. If a word or phrase is particularly contentious, an inline citation may be added next to that word or phrase within the sentence, but it is usually sufficient to add the citation to the end of the clause, sentence, or paragraph, so long as it's clear which source supports which part of the text.
Inline references can significantly bloat the wikitext in the edit window and can become confusing and difficult to manage. There are two main methods to avoid clutter in the edit window:
<ref name="Smith 2001, p99" />
.As with other citation formats, articles should not undergo large-scale conversion between formats without consensus to do so.
Note, however, that references defined in the reference list template can no longer be edited with the VisualEditor.
For multiple use of the same inline citation or footnote, you can use the named references feature, choosing a name to identify the inline citation, and typing <ref name="name">text of the citation</ref>
. Thereafter, the same named reference may be reused any number of times either before or after the defining use by typing the previous reference name, like this: <ref name="name" />
. The use of the slash before the >
means that the tag is self-closing, and the </ref>
used to close other references must not be used in addition.
The text of the name
can be almost anything—apart from being completely numeric. If spaces are used in the text of the name
, the text must be placed within double quotes. Placing all named references within double quotes may be helpful to future editors who do not know that rule. To help with page maintenance, it is recommended that the text of the name
have a connection to the inline citation or footnote, for example "author year page": <ref name="Smith 2005 p94">text of the citation</ref>
.
Use straight quotation marks "
to enclose the reference name. Do not use curly quotation marks “”
. Curly marks are treated as another character, not as delimiters. The page will display an error if one style of quotation marks is used when first naming the reference, and the other style is used in a repeated reference, or if a mix of styles is used in the repeated references.
When an article cites many different pages from the same source, to avoid the redundancy of many big, nearly identical full citations, most Wikipedia editors use one of these options:
|pages=
parameter of the {{cite xxx}} templates (can become confusing for large number of pages){{rp}}
or {{r}}
templates to specify the pageThe use of ibid., id., or similar abbreviations is discouraged, as they may become broken as new references are added (op. cit. is less problematic in that it should refer explicitly to a citation contained in the article; however, not all readers are familiar with the meaning of the terms). If the use of ibid is extensive, tag the article using the {{ibid}} template.
Listed below is the information that a typical inline citation or general reference will provide, though other details may be added as necessary. This information is included in order to identify the source, assist readers in finding it, and (in the case of inline citations) indicate the place in the source where the information is to be found. (If an article uses short citations, then the inline citations will refer to this information in abbreviated form, as described in the relevant sections above.)
In general, the citation information should be cited as it appears in the original source. For example, the album notes from Hurts 2B Human should not be cited as being from the album Hurts to be Human, or an X (formerly Twitter) user named "i😍dogs" should not be cited as "idogs". Retain the original special glyphs and spelling.
Citations for books typically include:
Some edited books have individually authored chapters. Citations for these chapters are recommended. They typically include:
In some instances, the verso of a book's title page may record, "Reprinted with corrections XXXX" or similar, where "XXXX" is a year. This is a different version of a book in the same way that different editions are different versions. Note this in your citation. See § Dates and reprints for further information.
Citations for journal articles typically include:
Citations for newspaper articles typically include:
Citations for World Wide Web pages typically include:
Citations for sound recordings typically include:
Do not cite an entire body of work by one performer. Instead, make one citation for each work your text relies on.
Citations for films, TV episodes, or video recordings typically include:
Wikidata is largely user-generated, and articles should not directly cite Wikidata as a source (just as it would be inappropriate to cite other Wikipedias' articles as sources).
But Wikidata's statements can be directly transcluded into articles; this is usually done to provide external links or infobox data. For example, more than two million external links from Wikidata are shown through the {{Authority control}} template. There has been controversy over the use of Wikidata in the English Wikipedia due to vandalism and its own sourcing. While there is no consensus on whether information from Wikidata should be used at all, there is general agreement that any Wikidata statements that are transcluded need to be just as – or more – reliable compared to Wikipedia content. As such, Module:WikidataIB and some related modules and templates filter Wikidata statements not supported by a reference by default; however, other modules and templates, such as Module:Wikidata, do not.
To transclude an item from Wikidata, the QID (Q number) of an item in Wikidata needs to be known. QID can by found by searching for an item by the name or DOI in Wikidata. A book, a journal article, a musical recording, sheet music or any other item can be represented by a structured item in Wikidata.
The {{Cite Q}} template can be used to cite works whose metadata is held in Wikidata, provided the cited work meets Wikipedia's standards. As of December 2020, {{Cite Q}}
does not support "last, first" or Vancouver-style author name lists, so it should not be used in articles in which "last, first" or Vancouver-style author names are the dominant citation style.
See also:
When citing lengthy sources, you should identify which part of a source is being cited.
Specify the page number or range of page numbers. Page numbers are not required for a reference to the book or article as a whole. When you specify a page number, it is helpful to specify the version (date and edition for books) of the source because the layout, pagination, length, etc. can change between editions.
If there are no page numbers, whether in ebooks or print materials, then you can use other means of identifying the relevant section of a lengthy work, such as the chapter number, the section title, or the specific entry.
In some works, such as plays and ancient works, there are standard methods of referring to sections, such as "Act 1, scene 2" for plays and Bekker numbers for Aristotle's works. Use these methods whenever appropriate.
Specify the time at which the event or other point of interest occurs. Be as precise as possible about the version of the source that you are citing; for example, movies are often released in different editions or "cuts". Due to variations between formats and playback equipment, precision may not be accurate in some cases. However, many government agencies do not publish minutes and transcripts but do post video of official meetings online; generally the subcontractors who handle audio-visual are quite precise.
A citation ideally includes a link or ID number to help editors locate the source. If you have a URL (web page) link, you can add it to the title part of the citation, so that when you add the citation to Wikipedia the URL becomes hidden and the title becomes clickable. To do this, enclose the URL and the title in square brackets—the URL first, then a space, then the title. For example:
''''. International Agency For Research On Cancer (IARC). 66: 97–104. 13–20 February 1996.
For web-only sources with no publication date, the "Retrieved" date (or the date you accessed the web page) should be included, in case the web page changes in the future. For example: Retrieved 15 July 2011 or you can use the access-date parameter in the automatic Wikipedia:refToolbar 2.0 editing window feature.
You can also add an ID number to the end of a citation. The ID number might be an ISBN for a book, a DOI (digital object identifier) for an article or some e-books, or any of several ID numbers that are specific to particular article databases, such as a PMID number for articles on PubMed. It may be possible to format these so that they are automatically activated and become clickable when added to Wikipedia, for example by typing ISBN (or PMID) followed by a space and the ID number.
If your source is not available online, it should be available in reputable libraries, archives, or collections. If a citation without an external link is challenged as unavailable, any of the following is sufficient to show the material to be reasonably available (though not necessarily reliable): providing an ISBN or OCLC number; linking to an established Wikipedia article about the source (the work, its author, or its publisher); or directly quoting the material on the talk page, briefly and in context.
Links to long PDF documents can be made more convenient by taking readers to a specific page with the addition of #page=n
to the document URL, where n
is the page number. For example, using https://www.domain.com/document.pdf#page=5
as the citation URL displays page five of the document in any PDF viewer that supports this feature. If the viewer or browser does not support it, it will display the first page instead.
Google Books sometimes allows numbered book pages to be linked to directly. Page links should only be added when the book is available for preview; they will not work with snippet view. Keep in mind that availability varies by location. No editor is required to add page links, but if another editor adds them, they should not be removed without cause; see the October 2010 RfC for further information.
These can be added in several ways (with and without citation templates):
In edit mode, the URL for p. 18 of A Theory of Justice can be entered like this using the {{Cite book}} template:
{{cite book |last=Rawls |first=John |date=1971 |title=A Theory of Justice |url=https://books.google.com/books?id=kvpby7HtAe0C&pg=PA18 |publisher=Harvard University Press |page=18}}
or like this, in the first of the above examples, formatted manually:
Rawls, John. . Harvard University Press, 1971, p. 18.
When the page number is a Roman numeral, commonly seen at the beginning of books, the URL looks like this for page xvii (Roman numeral 17) of the same book:
https://books.google.com/books?id=kvpby7HtAe0C&pg=PR17
The &pg=PR17 indicates "page, Roman, 17", in contrast to the &pg=PA18, "page, Arabic, 18" the URL given earlier.
You can also link to a tipped-in page, such as an unnumbered page of images between two regular pages. (If the page contains an image that is protected by copyright, it will be replaced by a tiny notice saying "copyrighted image".) The URL for eleventh tipped-in page inserted after page 304 of The Selected Papers of Elizabeth Cady Stanton and Susan B. Anthony, looks like this:
https://books.google.com/books?id=dBs4CO1DsF4C&pg=PA304-IA11
The &pg=PA304-IA11 can be interpreted as "page, Arabic, 304; inserted after: 11".
Note that some templates properly support links only in parameters specifically designed to hold URLs like |url=
and |archive-url=
and that placing links in other parameters may not link properly or will cause mangled COinS metadata output. However, the |page=
and |pages=
parameters of all Citation Style 1/Citation Style 2 citation templates, the family of {{sfn}}- and {{harv}}-style templates, as well as {{r}}, {{rp}} and {{ran}} are designed to be safe in this regard as well.
Citer may be helpful.
Users may also link the quotation on Google Books to individual titles, via a short permalink which ends with their related ISBN, OCLC or LCCN numerical code, e.g.:
https://books.google.com/books?vid=ISBN0521349931
, a permalink to the Google book with the ISBN code 0521349931.
For further details, you may see How-to explanation on support.google.com.
"Say where you read it" follows the practice in academic writing of citing sources directly only if you have read the source yourself. If your knowledge of the source is secondhand—that is, if you have read Jones (2010), who cited Smith (2009), and you want to use what Smith (2009) said—make clear that your knowledge of Smith is based on your reading of Jones.
When citing the source, write the following (this formatting is just an example):
John Smith (2009). Name of Book I Haven't Seen, Cambridge University Press, p. 99, cited in Paul Jones (2010). Name of Encyclopedia I Have Seen, Oxford University Press, p. 29.
Or if you are using short citations:
Smith (2009), p. 99, cited in Jones (2010), p. 29.
The same principle applies when indicating the source of images and other media files in an article.
Note: The advice to "say where you read it" does not mean that you have to give credit to any search engines, websites, libraries, library catalogs, archives, subscription services, bibliographies, or other sources that led you to Smith's book. If you have read a book or article yourself, that's all you have to cite. You do not have to specify how you obtained and read it.
So long as you are confident that you read a true and accurate copy, it does not matter whether you read the material using an online service like Google Books; using preview options at a bookseller's website like Amazon; through your library; via online paid databases of scanned publications, such as JSTOR; using reading machines; on an e-reader (except to the extent that this affects page numbering); or any other method.
Date a book that is identically reprinted or printed-on-demand to the first date in which the edition became available. For example, if an edition of a book was first released in 2005 with an identical reprinting in 2007, date it to 2005. If substantive changes were made in a reprint, sometimes marked on the verso with "Reprinted with corrections", note the edition and append the corrected reprint year to it (e.g. "1st ed. reprinted with corrections 2005").
Editors should be aware that older sources (especially those in the public domain) are sometimes republished with modern publication dates; treat these as new publications. When this occurs and the citation style being used requires it, cite both the new and original publication dates, e.g.:
This is done automatically in the {{citation}} and {{cite book}} templates when you use the |orig-date=
parameter.
Alternately, information about the reprint can be appended as a textual note:
Publication dates, for both older and recent sources, should be written with the goal of helping the reader find the publication and, once found, confirm that the correct publication has been located. For example, if the publication date bears a date in the Julian calendar, it should not be converted to the Gregorian calendar.
If the publication date was given as a season or holiday, such as "Winter" or "Christmas" of a particular year or two-year span, it should not be converted to a month or date, such as July–August or December 25. If a publication provided both seasonal and specific dates, prefer the specific one.
In most cases it is sufficient for a citation footnote simply to identify the source (as described in the sections above); readers can then consult the source to see how it supports the information in the article. Sometimes, however, it is useful to include additional annotation in the footnote, for example to indicate precisely which information the source is supporting (particularly when a single footnote lists more than one source – ).
A footnote may also contain a relevant quotation from the source. This is especially helpful when the cited text is long or dense. A quotation allows readers to immediately identify the applicable portion of the reference. Quotes are also useful if the source is not easily accessible. However, caution should be exercised, as always, to avoid copyright violations.
In the case of non-English sources, it may be helpful to quote from the original text and then give an English translation. If the article itself contains a translation of a quote from such a source (without the original), then the original should be included in the footnote.
This section describes how to add footnotes and also describes how to create a list of full bibliography citations to support shortened footnotes.
The first editor to add footnotes to an article must create a dedicated citations section where they are to appear. Any reasonable name may be chosen. The most frequent choice is "References". Other options in diminishing order of popularity are, "Notes", "Footnotes", or "Works cited", although these are more often used to distinguish between multiple end-matter sections or subsections.
For an example of headings of a notes section, see the article Tezcatlipoca.
A general reference is a citation to a reliable source that supports content, but is not linked to any particular text in the article through an inline citation. General references are usually listed at the end of the article in a "References" section, and are usually sorted by the last name of the author or the editor. General reference sections are most likely to be found in underdeveloped articles, especially when all article content is supported by a single source. The disadvantage of general references is that text–source integrity is lost, unless the article is very short. They are frequently reworked by later editors into inline citations.
The appearance of a general references section is the same as those given above in the sections on short citations and parenthetical references. If both cited and uncited references exist, their distinction can be highlighted with separate section names, e.g., "References" and "General references".
With some exceptions discussed below, citations appear in a single section containing only the <references />
tag or the {{Reflist}}
template. For example:
== References == {{Reflist}}
or
== References == <references />
The footnotes will then automatically be listed under that section heading. Each numbered footnote marker in the text is a clickable link to the corresponding footnote, and each footnote contains a caret that links back to the corresponding point in the text.
Scrolling lists, or lists of citations appearing within a scroll box, should never be used. This is because of issues with readability, browser compatibility, accessibility, printing, and site mirroring.
If an article contains a list of general references, this is usually placed in a separate section, titled, for example, "References". This usually comes immediately after the section(s) listing footnotes, if any. (If the general references section is called "References", then the citations section is usually called "Notes".)
If an article contains both footnoted citations and other (explanatory) footnotes, then it is possible (but not necessary) to divide them into two separate lists using footnotes groups. The explanatory footnotes and the citations are then placed in separate sections, called (for example) "Notes" and "References", respectively.
Another method of separating explanatory footnotes from footnoted references is using {{efn}} for the explanatory footnotes. The advantage of this system is that the content of an explanatory footnote can in this case be referenced with a footnoted citation. When explanatory footnotes and footnoted references are not in separate lists, {{refn}} can be used for explanatory footnotes containing footnoted citations.
Combine precisely duplicated full citations, in keeping with the existing citation style (if any). In this context "precisely duplicated" means having the same content, not necessarily identical strings ("The New York Times" is the same as "NY Times"; different access-dates are not significant). Do not discourage editors, particularly inexperienced ones, from adding duplicate citations when the use of the source is appropriate, because a duplicate is better than no citation. But any editor should feel free to combine them, and doing so is the best practice on Wikipedia.
Citations to different pages or parts of the same source can also be combined (preserving the distinct parts of the citations), as described in Help:References and page numbers. Any method that is consistent with the existing citation style (if any) may be used, or consensus can be sought to change the existing style. Some tools are listed at Help:Citation tools § Duplicate reference finders.
While citations should aim to provide the information listed above, Wikipedia does not have a single house style, though citations within any given article should follow a consistent style. A number of citation styles exist, including those described in the Wikipedia articles for Citation, APA style, ASA style, MLA style, The Chicago Manual of Style, Author-date referencing, the Vancouver system and Bluebook.
Although nearly any consistent style may be used, avoid all-numeric date formats other than YYYY-MM-DD, because of the ambiguity concerning which number is the month and which the day. For example, 2002-06-11 may be used, but not 11/06/2002. The YYYY-MM-DD format should in any case be limited to Gregorian calendar dates where the year is after 1582. Because it could easily be confused with a range of years, the format YYYY-MM (for example: 2002-06) is not used.
For more information on the capitalization of cited works, see Wikipedia:Manual of Style/Capital letters § All caps and small caps.
Editors should not attempt to change an article's established citation style, merely on the grounds of personal preference or to make it match other articles, without first seeking consensus for the change.
As with spelling differences, it is normal practice to defer to the style used by the first major contributor or adopted by the consensus of editors already working on the page, unless a change in consensus has been achieved. If the article you are editing is already using a particular citation style, you should follow it; if you believe it is inappropriate for the needs of the article, seek consensus for a change on the talk page. If you are the first contributor to add citations to an article, you may choose whichever style you think best for the article. However, since 5 September 2020, inline parenthetical referencing is a deprecated citation style on English-language Wikipedia.
If all or most of the citations in an article consist of bare URLs, or otherwise fail to provide needed bibliographic data – such as the name of the source, the title of the article or web page consulted, the author (if known), the publication date (if known), and the page numbers (where relevant) – then that would not count as a "consistent citation style" and can be changed freely to insert such data. The data provided should be sufficient to uniquely identify the source, allow readers to find it, and allow readers to initially evaluate a source without retrieving it.
The following are standard practice:
<ref>
markup problems: an improvement because it helps the citations to be parsed correctly;When an article is already consistent, avoid:
Since September 2020, inline parenthetical referencing has been deprecated on Wikipedia. This includes short citations in parentheses placed within the article text itself, such as (Smith 2010, p. 1). This does not affect short citations that use <ref>
tags, which are not inline parenthetical references; see the section on short citations above for that method. As part of the deprecation process in existing articles, discussion of how best to convert inline parenthetical citations into currently accepted formats should be held if there is objection to a particular method.
This should no longer be used, and should be replaced with footnotes if encountered:
The Sun is pretty big (Miller 2005, p. 1), but the Moon is not so big (Brown 2006, p. 2). The Sun is also quite hot (Miller 2005, p. 3).
As noted above under "What information to include", it is helpful to include hyperlinks to source material, when available. Here we note some issues concerning these links.
Embedded links to external websites should not be used as a form of inline citation, because they are highly susceptible to linkrot. Wikipedia allowed this in its early years—for example by adding a link after a sentence, like this: , which is rendered as: . This is no longer recommended. Raw links are not recommended in lieu of properly written out citations, even if placed between ref tags, like this <ref></ref>
. Since any citation that accurately identifies the source is better than none, do not revert the good-faith addition of partial citations. They should be considered temporary, and replaced with more complete, properly formatted citations as soon as possible.
Embedded links should never be used to place external links in the content of an article, like this: "Example Inc. announced their latest product ...".
A convenience link is a link to a copy of your source on a web page provided by someone other than the original publisher or author. For example, a copy of a newspaper article no longer available on the newspaper's website may be hosted elsewhere. When offering convenience links, it is important to be reasonably certain that the convenience copy is a true copy of the original, without any changes or inappropriate commentary, and that it does not infringe the original rights-holders' copyrights. Accuracy can be assumed when the hosting website appears reliable.
For academic sources, the convenience link is typically a reprint provided by an open-access repository, such as the author's university's library or institutional repository. Such green open access links are generally preferable to paywalled or otherwise commercial and unfree sources.
Where several sites host a copy of the material, the site selected as the convenience link should be the one whose general content appears most in line with Wikipedia:Neutral point of view and Wikipedia:Verifiability.
If your source is not available online, it should be available in libraries, archives, or collections. If a citation without an external link is challenged as unavailable, any of the following is sufficient to show the material to be reasonably available (though not necessarily reliable): providing an ISBN or OCLC number; linking to an established Wikipedia article about the source (the work, its author, or its publisher); or directly quoting the material on the talk page, briefly and in context.
For a source available in hardcopy, microform, and/or online, omit, in most cases, which one you read. While it is useful to cite author, title, edition (1st, 2nd, etc.), and similar information, it generally is not important to cite a database such as ProQuest, EBSCOhost, or JSTOR (see the list of academic databases and search engines) or to link to such a database requiring a subscription or a third party's login. The basic bibliographic information you provide should be enough to search for the source in any of these databases that have the source. Don't add a URL that has a part of a password embedded in the URL. However, you may provide the DOI, ISBN, or another uniform identifier, if available. If the publisher offers a link to the source or its abstract that does not require a payment or a third party's login for access, you may provide the URL for that link. If the source only exists online, give the link even if access is restricted (see WP:PAYWALL).
To help prevent dead links, persistent identifiers are available for some sources. Some journal articles have a digital object identifier (DOI); some online newspapers and blogs, and also Wikipedia, have permalinks that are stable. When permanent links aren't available, consider making an archived copy of the cited document when writing the article; on-demand web archiving services such as the Wayback Machine (https://web.archive.org/save) or archive.today (https://archive.today) are fairly easy to use (see pre-emptive archiving).
Do not delete a citation merely because the URL is not working. Dead links should be repaired or replaced if possible. If you encounter a dead URL being used as a reliable source to support article content, follow these steps prior to deleting it:
site:nytimes.com "the goose is loose"
.|access-date=
. If that parameter is not specified, a search of the article's revision history can be performed to determine when the link was added to the article.|archive-url=
, |archive-date=
and |url-status=
parameters. The primary link is switched to the archive link when |url-status=dead
. This retains the original link location for reference.|url-status=usurped
to hide the original website link in the citation.{{dead link|date=December 2024}}
, so that you can estimate how long the link has been dead.javascript:void(window.open('https://web.archive.org/web/*/'+location.href))
javascript:void(window.open('https://archive.today/'+location.href))
javascript:void(window.open('https://www.webarchive.org.uk/mementos/search/'+encodeURIComponent(location.href)+'?referrer='+encodeURIComponent(document.referrer)))
{{citation needed}}
. It may be appropriate for you to move the citation to the talk page with an explanation, and notify the editor who added the now-dead link.When using inline citations, it is important to maintain text–source integrity. The point of an inline citation is to allow readers and other editors to see which part of the material is supported by the citation; that point is lost if the citation is not clearly placed. The distance between material and its source is a matter of editorial judgment, but adding text without clearly placing its source may lead to allegations of original research, of violations of the sourcing policy, and even of plagiarism.
Editors should exercise caution when rearranging or inserting material to ensure that text–source relationships are maintained. References should not be moved if doing so might break the text–source relationship.
If a sentence or paragraph is footnoted with a source, adding new material that is not supported by the existing source to the sentence/paragraph, without a source for the new text, is highly misleading if placed to appear that the cited source supports it. When new text is inserted into a paragraph, make sure it is supported by the existing or a new source. For example, when editing text originally reading
- ^ Miller, Edward. The Sun. Academic Press, 2005, p. 1.
an edit that does not imply that the new material is supported by the same reference is
The sun is pretty big. The sun is also quite hot.
Notes
Do not add other facts or assertions into a fully cited paragraph or sentence:
The sun is pretty big, but the moon is not so big. The sun is also quite hot.
Notes
Include a source to support the new information. There are several ways to write this, including:
The sun is pretty big, but the moon is not so big. The sun is also quite hot.
Notes
There is no consensus for a specific ordering of citations, and editors should not edit-war over it, nor make mass changes of ordering to suit personal preferences. In particular, references need not be moved solely to maintain the numerical order of footnotes as they appear in the article.
Sometimes the article is more readable if multiple citations are bundled into a single footnote. For example, when there are multiple sources for a given sentence, and each source applies to the entire sentence, the sources can be placed at the end of the sentence, like this: Or they can be bundled into one footnote at the end of the sentence or paragraph, like this:
Bundling is also useful if the sources each support a different portion of the preceding text, or if the sources all support the same text. Bundling has several advantages:
To concatenate multiple citations for the same content into a single footnote, there are several layouts available, as illustrated below:
The sun is pretty big, but the moon is not so big. The sun is also quite hot.
Notes
Use {{Unbulleted list citebundle}}:
Use an inline paragraph:
Use a bullet list:
This last approach needs an introductory line like "Multiple sources:" to prevent an unwanted linebreak after the footnote number.
Simply using line breaks to separate list items breaches MOS:Accessibility § Nobreaks: "
<br />
line breaks ... should not be used."{{Unbulleted list citebundle}}
a.k.a. {{Multiref}}
was made specifically for this purpose. Some other templates in the same vein are listed at the disambiguation page Template:Multiple references.
Within a given article only a single layout should generally be used, except that inline may always be appropriate for shortened references, often all for the same statement:
In-text attribution is the attribution inside a sentence of material to its source, in addition to an inline citation after the sentence. In-text attribution may need to be used with direct speech (a source's words between quotation marks or as a block quotation); indirect speech (a source's words modified without quotation marks); and close paraphrasing. It may also be used when loosely summarizing a source's position in your own words, and it should always be used for biased statements of opinion. For certain frequently discussed sources, in-text attribution is always recommended. It avoids inadvertent plagiarism and helps the reader see where a position is coming from. An inline citation should follow the attribution, usually at the end of the sentence or paragraph in question.
For example:
To reach fair decisions, parties must consider matters as if behind a veil of ignorance.
John Rawls argues that, to reach fair decisions, parties must consider matters as if behind a veil of ignorance.
John Rawls argues that, to reach fair decisions, parties must consider matters as if "situated behind a veil of ignorance".
When using in-text attribution, make sure it doesn't lead to an inadvertent neutrality violation. For example, the following implies parity between the sources, without making clear that the position of Darwin is the majority view:
Charles Darwin says that human beings evolved through natural selection, but John Smith writes that we arrived here in pods from Mars.
Humans evolved through natural selection, as first explained in Charles Darwin's The Descent of Man, and Selection in Relation to Sex.
Neutrality issues apart, there are other ways in-text attribution can mislead. The sentence below suggests The New York Times has alone made this important discovery:
According to The New York Times, the sun will set in the west this evening.
The sun sets in the west each evening.
It is preferable not to clutter articles with information best left to the references. Interested readers can click on the ref to find out the publishing journal:
In an article published in The Lancet in 2012, researchers announced the discovery of the new tissue type.
Researchers announced the new tissue type in 2012.
Simple facts such as this can have inline citations to reliable sources as an aid to the reader, but normally the text itself is best left as a plain statement without in-text attribution:
By mass, oxygen is the third most abundant element in the universe after hydrogen and helium.
If an article has no references at all, then:
{{unreferenced}}
template and consider nominating it for deletion.For individual claims in an article not supported by a reference:
{{uw-unsourced1}}
template may be placed on their talk page.{{citation needed}}
or {{dubious}}
tag against the added text.Citation templates can be used to format citations in a consistent way. The use of citation templates is neither encouraged nor discouraged: an article should not be switched between templated and non-templated citations without good reason and consensus – see "Variation in citation methods", above.
If citation templates are used in an article, the parameters should be accurate. It is inappropriate to set parameters to false values to cause the template to render as if it were written in some style other than the style normally produced by the template (e.g., MLA style).
Citations may be accompanied by metadata, though it is not mandatory. Most citation templates on Wikipedia use the COinS standard. Metadata such as this allow browser plugins and other automated software to make citation data accessible to the user, for instance by providing links to their library's online copies of the cited works. In articles that format citations manually, metadata may be added manually in a span, according to the COinS specification.
How to cite
<ref>
parser hooksCitation problems
Changing citation style formats