Wikipedia:Citing sources
From Wikipedia, the free encyclopedia
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This page documents an English Wikipedia style guideline. It is a generally accepted standard that editors should attempt to follow, though it is best treated with common sense and the occasional exception. Any substantive edit to this page should reflect consensus. When in doubt, discuss first on the talk page. |
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This page in a nutshell: This citing sources guideline (a) discusses when to use citations, (b) shows how to format individual citations, and (c) provides methods for presenting citations within Wikipedia articles. |
| Wikipedia policy |
|---|
| Global principles |
| What Wikipedia is not Ignore all rules |
| Content standards |
| Neutral point of view Verifiability No original research Biographies of living persons |
| Working with others |
| Civility No personal attacks Harassment No legal threats Consensus Dispute resolution |
| More |
| Full list of policies List of guidelines |
A citation is a line of text that uniquely identifies a source. For example:
- Ritter, R. (2002). The Oxford Style Manual. Oxford University Press. ISBN 0-19-860564-1.
It allows a reader to find the source and verify that it supports material in Wikipedia.
When to use. Sources should be cited when adding material that is challenged or likely to be challenged, when quoting someone, when adding material to the biography of a living person, when checking content added by others, and when uploading an image
How to format. While you should attempt to format a citation as described below in the How to format citations section of this guideline, it is even more important that material in Wikipedia is verifiable. Add your source even if you are unsure of how to properly format the citation—provide enough information to identify the source, and others will improve the formatting.
How to present. Citations are usually presented within articles using one of the methods described below in the How to present citations section of this guideline. Each article should use the same method throughout—if an article already has some citations, an editor should adopt the method already in use or seek consensus before changing it.
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Quick summary
Footnote summary
The most common method for citing sources in Wikipedia is footnote referencing. The basic steps are:
- Immediately after the text that requires a source, add <ref>details of the citation</ref>. This will appear as a numbered superscript link.
- If you are working on a new page, or adding the first footnote to a page, add the following wiki markup at the bottom of the page, where the reference listing will appear:
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==Notes==
<references />OR ==Notes==
{{reflist}}
- Your details of the citation text will appear in the appropriate section towards the bottom of the article, listed along with other footnotes; clicking on the numbered superscript link in the text will jump to it.
General reference summary
If a source supports a significant amount of the material in an article, another method is general referencing. The basic steps are:
- If you are working on a new page, or adding the first references to a page, add the following wiki markup at the bottom of the page, where the reference listing will appear:
- ==References==
- * details of the citation
Your details of the citation text will appear in the appropriate section towards the bottom of the article, listed in a bullet format. Over-reliance on general referencing in an article may lead to that article being tagged with the {{nofootnotes}} tag. For book references, use of general referencing may lead to individual references being tagged with {{page number}} tags.
When to cite sources
Wikipedia is by its very nature a work by people with widely different knowledge and skills. The reader needs to be assured that the material within it is reliable. The purpose of citing sources is:
- To ensure that the content of articles can be checked by any reader or editor.
- To show that your edit is not original research and to reduce editorial disputes.
- To avoid claims of plagiarism and copying.
- To help users find additional information on the topic.
- To ensure that material about living persons complies with biography policy.
- To improve the credibility of Wikipedia.
When adding material that is challenged or likely to be challenged
Wikipedia:Verifiability says: "All quotations and any material challenged or likely to be challenged should be attributed to a reliable, published source using an inline citation."
The need for citations is especially important when writing about opinions held on a particular issue. Avoid weasel words where possible, such as, "Some people say ..." Instead, make your writing verifiable: find a specific person or group who holds that opinion and give a citation to a reputable publication in which they express that opinion. Remember that Wikipedia is not a place for expressing your own opinions or for original research. Opinions, data and statistics, and statements based on someone's scientific work should be cited and attributed to their authors in the text.
When quoting someone
You should always add a citation when quoting published material, and the citation should be placed directly after (or just before) the quotation, which should be enclosed within double quotation marks—"like this"—or single quotation marks if it is a quote-within-a-quote—"and here is such a 'quotation' as an example." For long quotes, you may wish to use Quotation templates.
When adding material to the biography of a living person
Biographies of living persons should be sourced with particular care, for legal and ethical reasons. All contentious material about living persons must cite a reliable source. If you find unsourced or poorly sourced contentious material about a living person—whether in an article or on a talk page—remove it immediately! Do not leave it in the article while you request a source. Do not move it to the talk page. This applies whether the material is in a biography or any other article.
When checking content added by others
You can also add sources for material you did not write. Adding citations is an excellent way to contribute to Wikipedia. See Wikipedia:WikiProject Fact and Reference Check for organized efforts to add citations.
When uploading an image
Images must include source details and a copyright tag on the image description page. It is important that you list the author of the image if known (especially if different from the source), which is important both for copyright and for informational purposes. Some copyright licenses require that the original author receive credit for their work.
- If you download an image from the web, you should give the URL:
- Source: Downloaded from http://news.bbc.co.uk/1/hi/world/europe/4280841.stm
- If you got the image from an offline source, you should specify:
- Source: Scanned from public record #5253 on file with Anytown, Somestate public surveyor
Any image with a non-free copyright license must be accompanied by a non-free use rationale (also called a fair use rationale) for each article in which the image is used.
Qualifying sources
Sources for uncontentious statements do not necessarily need to be described beyond adding the citation. No further description would be needed with the following, for example:
- The word caffeine comes from the French term for coffee: café.[1]
However, points which are more controversial, and about which there are contradictory studies or different opinions, may need to include more descriptive context to qualify the nature of the source. For example (from Super-recursive algorithm):
- Martin Davis has described some of Burgin's claims as "misleading".[2]</d