WP:CITE


 * WP:CITE, WP:REF, and WP:CS redirect here. You may also be looking for Citing Wikipedia, Reference desk, Cheatsheet, WikiProject Computer science or WikiProject Coronation Street. For citation templates, see WP:CIT.

A citation is a line of text that uniquely identifies a source. For example:


 * Ritter, Ron. The Oxford Style Manual, Oxford University Press, 2002, p. 1.

When to cite sources: The policy on sourcing is Verifiability, which requires inline citations for any material challenged or likely to be challenged, and for all quotations. The policy is strictly applied to all material in the mainspace&mdash;articles, lists, and sections of articles&mdash;without exception, and in particular to information about living persons: unsourced contentious or negative material about living persons must be removed immediately. When an image is uploaded, the uploader must state where the image came from, and its copyright status. If the image comes from an online site, a link to the source page is normally provided.

How to write citations: While you should try to write citations correctly, what matters is that you add your source&mdash;provide enough information to identify the source, and others will improve the formatting if needed. Each article should use the same citation method throughout. If an article already has citations, adopt the method in use or seek consensus before changing it.

In the event of a contradiction between this page and the sourcing policy, Verifiability, the policy takes priority, and this page should be updated to reflect it.

Use of terms
A "citation" is a line of text that identifies a source. The word "source" has three related meanings on Wikipedia: the piece of work itself, the creator of the work, and the publisher of the work; see Verifiability. The word "reference" may refer to the citation, the source, or both.

A common system of citation on Wikipedia is a footnote system, where citations appear in footnotes. The terms "footnote" and "note" are used interchangeably. There is no separate usage of the term "endnote," because each Wikipedia article, like other HTML documents, is considered to be only one page even if it is displayed across several screens. The terms "Further reading" and "External links" are used as section headings for lists of additional general texts on a topic for those interested.

Summary
Footnote referencing is the most common method for citing sources in Wikipedia. The basic steps are:


 * Ensure that the following wiki markup is at the bottom of the page - if not enter it (the alternative titles "References" or "Footnotes" may be used rather than "Notes"):


 * {| style="background:transparent;"

 and  ) in place of the   tag. These reduce clutter within articles, by putting all the citation details in the section at the end where the footnotes are displayed. As with other citation formats, these should not be added to articles that already have a stable referencing system, unless there is consensus to do so. When in doubt, use the referencing system added by the first major contributor to use a consistent style.
 *  ==Notes== 
 *  ==Notes== 

The example below shows what list-defined references look like in the edit box:   The Sun is pretty big, &lt;ref name=Miller2005p23/>

but the Moon is not so big. &lt;ref name=Brown2006/>

The Sun is also quite hot. &lt;ref name=Miller2005p34/>

&#61;=Notes==

  

Below is how this would look in the article, once you had previewed or saved your edited section:  The Sun is pretty big,[1] but the Moon is not so big.[2] The Sun is also quite hot.[3]

Notes

^ Miller, E: The Sun, page 23. Academic Press, 2005. ^ Brown, R: "Size of the Moon", Scientific American, 51(78):46. ^ Miller, E: The Sun, page 34. Academic Press, 2005.</li> </ol>

Defined references must be used within the body; unused references will show an error message. However, non-list-defined references (i.e. ordinary footnote references fully enclosed with tags) will display as normal along with any list-defined ones.

Parenthetical referencing
Two forms of parenthetical referencing may also be used in Wikipedia: author-date referencing (APA style, Harvard style, or Chicago style); and author-title or author-page referencing (MLA style or Chicago style). For a discussion of the advantages and disadvantages, see Pros & Cons.

In parenthetical citations, a short version of the citation is added in parentheses just after the point it is supporting, comprising only the surname of the author(s) and the year of publication, and possibly page numbers (APA style); or the surname of the author(s) and possibly short titles and/or page numbers (MLA style).

Using author-date parenthetical references, the inline citation usually looks like: (Author 2006:28) or (Author 2006, p. 28). The full citation is then added at the end of the article to a "References" or "Works cited" section. This list of full citations is usually ordered alphabetically by author name. As with shortened notes, the inline citation and the full citation may be linked so that the reader may click on the inline citation to highlight the full citation (see linking inline and full citations).

Below is an edit-mode view of adding author-date citations to an article: <blockquote style="color:#999; background:white; padding:1em; border:1px solid DarkSeaGreen;">  The Sun is pretty big (Miller 2005) ,

but the Moon is not so big (Brown 2006, p. 46).

The Sun is also quite hot (Miller 2005, p. 34).

&#61;= References ==

* '''Brown, R (2006). "Size of the Moon", Scientific American, 51(78)'''.

* '''Miller, E (2005). The Sun, Academic Press'''. </tt>

Below is how this would look once the edit has been saved: <blockquote style="background:white; padding:1em; border:1px solid #999;"> The Sun is pretty big (Miller 2005), but the Moon is not so big (Brown 2006, p. 46). The Sun is also quite hot (Miller 2005, p. 34).

References


 * Brown, R (2006). "Size of the Moon", Scientific American, 51(78).
 * Miller, E (2005). The Sun, Academic Press.

Embedded links
If a webpage is used as a source, it can be linked to directly within the article by enclosing the URL in square brackets just after the point it is supporting. When the edit is saved, only a number is visible within the text. For example, a citation of a newspaper article can be embedded by adding, which looks like

Embedded links should not be used to place external links to websites in the body of an article where they are not used to verify article content, but instead to direct readers to other websites. For example, do not spam links to companies' or organizations' websites in article text, like this: "Apple, Inc. announced their latest product..." Only links to pages that directly support claims made in the article should be embedded as links, and those embedded links should follow the formatting shown in the previous paragraph. InterWikimedia links to Wiktionary and Wikisource are sometimes appropriate in the body of an article; for details, see Wikimedia sister projects.

A full citation is also required in a References section at the end of the article. For example:

which appears as:


 * Plunkett, John. "Sorrell accuses Murdoch of panic buying", The Guardian, London, October 27, 2005.

Because of the difficulties in associating them with their appropriate full citations, the use of embedded links for inline citations is not recommended as a method of best practice and is not found in featured articles. It is easily converted to a shortened footnote or parenthetical reference.

Say where you found it
It is improper to take material from one source and attribute it to a different one. For example, a webpage may provide information that the page's author attributes to a book. Unless you examine the book yourself, your source is the webpage, not the book. You should also make clear, where appropriate, that the webpage cited the book. It can be important to be clear about this for two reasons: (a) because the credibility of your edit rests on the webpage, which may have misinterpreted the book, and (b) because it is sometimes preferable to cite the original source, especially where the issue is a contentious one.

For example, where Smith is the author of the book, and Jones the author of the webpage you have read, you could write: "Smith 2005, p. 100, cited in Jones 2010," between ref tags, with full citations in the References section. Or if you're using long citations in the text, you could write, again between ref tags: "Smith, John (2005). Name of Book. Cambridge University Press, p. 100, cited in Jones, Paul (2010). "About Me," Pauljones.com, accessed January 15, 2010. Note that it is always better to read the original source material yourself.

Non-English sources
Because this is the English Wikipedia, English-language sources should be used in preference to non-English language sources of equal caliber and content, though the latter are allowed where appropriate. When quoting a source in a different language, please provide both the original-language quotation and an English translation, in the text, in a footnote, or on the talk page as appropriate.

Convenience links
A convenience link is a link to a copy of your source on a webpage 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 publisher's copyright. Accuracy can be assumed when the hosting website appears reliable. 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 Neutral point of view and Verifiability.

Multimedia
Multimedia material should be referenced just like article text. Citations for a media file should appear on its file page. Image captions should be referenced as appropriate just like any other part of the article. If an infobox or table contains text that needs citing, but the box or table cannot incorporate an inline citation, the citation should appear in a caption or other text that discusses the material. A citation is not needed for descriptions such as alt text that are verifiable directly from the image itself. Material that identifies a source (e.g., the caption "Belshazzar's Feast (1635)" for File:Rembrandt-Belsazar.jpg) is considered attribution and normally does not need further citation.

Avoid scrolling lists
Scrolling lists, for example lists of citations appearing within a scroll box, should never be used because of issues with readability, accessibility, printing, and site mirroring. Additionally, it cannot be guaranteed that such lists will display properly in all web browsers. See this July 2007 discussion for more detail.

Consistent style
Citations in Wikipedia articles should use a consistent style. Any of the following styles are acceptable so long as each article is internally consistent. You should follow the style already established in an article, if it has one; where there is disagreement, the style used by the first editor to use one should be respected.

Similarly, there are several methods of internal formatting or markup that can used to create a given displayed citation. The best practice is for a given article to be consistent in internal markup or formatting. It is better to follow the patterns in place if an article has a stable citation structure. Changing existing citations from one format to another should generally be done only with local consensus, and should never be the subject of an edit war.

However, if an editor can provide a new relevant reference, either to new content or to existing unsourced content, it is more important for the citation to the reference to be recorded in some format. Another editor can always edit the reference to bring it into consistency with the style and formatting of the existing citations in the article.

Citation styles
There are a number of citation styles. See here for some examples. They all include the same information but vary in punctuation and the order of the author's name, publication date, title, and page numbers.

Full citations for books typically include:
 * name of the author(s)
 * year of publication in brackets
 * title of the book in italics
 * city of publication optional
 * name of the publisher
 * page number(s) where appropriate
 * ISBN optional
 * Full citations for individually authored chapters in books additionally include:
 * the book's overall editor
 * the title of the chapter
 * the page numbers for the chapter

Full citations for journal articles typically include:
 * name of the author(s)
 * year and sometimes month of publication
 * title of the article within quotation marks
 * name of the journal in italics
 * volume number, issue number (if the journal uses them), and page numbers (article numbers in some electronic journals)

Citations for newspaper articles typically include:
 * name of the newspaper in italics (required)
 * date of publication (required)
 * byline (author's name), if any
 * title of the article within quotation marks
 * city of publication, if not included in name of newspaper
 * page number(s) are optional

Citations for World Wide Web articles typically include:
 * name of the author(s)
 * title of the article within quotation marks
 * name of the website (linked to a Wikipedia article about the site if it exists, or to Website's "about" page)
 * date of publication
 * page number(s) (if applicable)
 * the date you retrieved it (required if the publication date is unknown)

Identifying parts of a source
You should identify any part of a source that you quote, paraphrase or cite; in the case of a book, specify the page number(s). It is also important to specify the version (date and edition for books) of the source because the layout, pagination, length, etc can change. Page numbers are especially important for lengthy non-indexed books, but they are not required for a reference to the source as a whole; for example when describing a complete book or article or when the source is used to illustrate a particular point of view.

Links and ID numbers
A citation ideally includes a link or ID number to help editors locate the source. If you have a URL (webpage) 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: "" For web-only sources with no publication date you should include a "Retrieved" date instead, in case the webpage changes in the future. For example: Retrieved 2008-07-15.

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 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) following by a space followed by 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.

Citation templates and tools

 * For a comparison of citations using templates with citations written freehand, see Wikipedia:Citing sources/Example edits for different methods.

Citation templates are used to format citations in a consistent way. The use of citation templates is neither encouraged nor discouraged. Templates may be used or removed at the discretion of individual editors, subject to agreement with other editors on the article. Because templates can be contentious, editors should not change an article with a distinctive citation format to another without gaining consensus. Where no agreement can be reached, defer to the style used by the first major contributor.

There are several webpages/tools that can help quickly produce a citation in a standard template format. You may only need one piece of information and they can fill in the rest of the details. The resulting citation will be enclosed in "cite" tags, and it will be formatted in a particular way depending on which kind of template is being used. You can then copy all the text from there. It may still require additional tags before you can add it to a Wikipedia article.

Metadata
Citations may be accompanied by metadata, though it is not mandatory. Most citation templates on Wikipedia use the COinS microformat. 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; or the templates Template:Citation metadata or Template:COinS can be used.

Citation processing tools

 * Template:Citation/core – a core template used by other citation templates
 * User:CitationTool – a tool for finding article-level citation errors and fixing them. Not currently functional.
 * Citation bot (formerly DOI bot) – a bot that automatically fixes common errors in individual citations, and adds missing fields

Programming tools

 * Wikicite is a free program that helps editors to create citations for their Wikipedia contributions using citation templates. It is written in Visual Basic .NET, making it suitable only for users with the .NET Framework installed on Windows, or, for other platforms, the Mono alternative framework. Wikicite and its source code is freely available, see the developer's page for further details.
 * Wikicite+ is a program based on the original Wikicite source code. It features extra validation, bug fixes, additional cite templates (such as cite episode) as well as tools for stub sorting and more. It is also available for free under the Apache License 2.0 and is open source.
 * pubmed2wiki.xsl a XSL stylesheet transforming the XML output of PubMed to Wikipedia refs.
 * User:Richiez has tools to automatically handle citations for a whole article at a time. Converts occurrences of or  to properly formatted footnote or Harvard style references. Written in ruby and requires a working installation with basic libraries.
 * RefTag by Apoc2400 creates a prefilled cite book template with various options from a Google Books URL. The page provides a bookmarklet for single-click transfer.

Citation export tools
You can insert a link beside each citation in Wikipedia, allowing you to export the citation to a reference manager such as EndNote. Just copy this code: to the end of Special:MyPage/monobook.js. Then, save the page and bypass your browser's cache.

Preventing and repairing dead links
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 archiving the referenced document when writing the article; on-demand web archiving services such as WebCite (http://www.webcitation.org) are fairly easy to use (see pre-emptive archiving).

Dead links should be repaired or replaced if possible. In most cases one of the following approaches will give an acceptable alternative.


 * First, check the link to confirm that it is dead. The site may have been temporarily down or have changed its linking structure. If the link has returned to service but has been labeled as a dead link, simply remove the labeling. See dead link.
 * If the document is no longer available at the original website, there may be a copy of the referenced document at a web archiving service. If so, update the citation to include a link to the archived copy of the referenced document.
 * The Internet Archive (http://www.archive.org/) has literally billions of archived webpages. Note that there may be a delay of six months before a recent link shows up there. See also the article Using the Wayback Machine.
 * WebCite is an "on-demand" archiving service (http://www.webcitation.org) that should also be checked.
 * If a good copy of the original document cannot be located, it may be possible to find a substitute. Enter key words or phrases or other content from the cited material into the referenced website's search engine, into a similar website's search engine, or into a general search engine such as Google.  (A search engine may hold a cached version of the dead link for a short time, which can help find a substitute.)  Or, browse the referenced document's website or similar websites.  If you find a new document that can serve as a substitute, update the dead link to refer to the new document.
 * Deactivate the dead link, and keep the citation information if still appropriate to the article. (This may happen, for example, when an online copy of material that originally appeared in print is no longer online.)  In the remaining citation, note that the dead link was found to be inactive on today's date. Even with an inactive link, the citation still records a source that was used, and provides a context for understanding archiving delays or for taking other actions.  In order to deactivate the dead link, do one of the following.
 * Turn the dead link into plain text. Remove only enough of the dead link's wikitext or markup language or URI scheme (square brackets, "http://", and so on) so that clicking on the link does not take you to its destination. This will make the link visible to both readers and editors of the article.
 * Turn the dead link into an HTML comment. Place HTML comment markup language around the link.  This will make the link disappear when reading the article, but will preserve the link for editors of the article.

If a dead link cannot be repaired or replaced, one option to consider is reworking the article section so that it no longer relies on the dead link, though this is not required. Regardless of whether a dead link can or cannot be repaired or replaced, remember that Wikipedia policy (including policy on sources and biographies of living persons) still applies.