Wikipedia:ATT

are , , and . These policies determine the type and quality of material that is acceptable in articles. Because the policies are complementary, they should not be interpreted in isolation from one another.

Reliable sources are credible published materials with a reliable publication process; their authors are generally regarded as trustworthy or authoritative in relation to the subject at hand. How reliable a source is depends on context. In general, the most reliable sources are books and journals published by universities; mainstream newspapers; and university level textbooks, magazines and journals that are published by known publishing houses. What these have in common is process and approval between document creation and publication. As a rule of thumb, the more people engaged in checking facts, analyzing legal issues, and scrutinizing the writing, the more reliable the publication. Material that is self-published is generally not regarded as reliable, but see below for exceptions. Any unsourced material may be removed, and in biographies of living persons contentious material that is unsourced or poorly sourced should be removed immediately.

Original research refers to material that is not attributable to a reliable, published source. This includes unpublished facts, arguments, ideas, statements, and neologisms; and any unpublished analysis or synthesis of published material that appears to advance a position. Material added to articles must be directly and explicitly supported by the cited sources.

Note the difference between unsourced material and original research:

The only way to demonstrate that material is not original research is to cite reliable sources that provide information directly related to the topic of the article, and to adhere to what those sources say.

Some sources pose special difficulties:

Questionable and self-published sources should not normally be used. There are three exceptions:

Certain red flags should prompt editors to examine the sources for a given claim:

Exceptional claims should be supported by the best sources, and preferably multiple reliable sources, especially regarding scientific or medical topics, historical events, politically charged issues, and biographies of living people.

Material counts as original research if it:

Editors often make the mistake of thinking that if A is published by a reliable source, and B is published by a reliable source, then A and B can be joined together in an article in order to advance position C. However, that would be an example of an unpublished synthesis of published material serving to advance a position, and it constitutes original research. "A and B, therefore C" is acceptable only if a reliable source has published this argument in relation to the topic of the article.

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