Here we go again (wikipedia)

[Adonai One]

What counts as a reliable source

The word "source" in Wikipedia has three meanings:

the type of the work (some examples include a document, an article, or a book)
the creator of the work (for example, the writer)
the publisher of the work (for example, Oxford University Press).

All three can affect reliability.

Base articles on reliable, third-party, published sources with a reputation for fact-checking and accuracy. Source material must have been published, the definition of which for our purposes is "made available to the public in some form".[6] Unpublished materials are not considered reliable. Use sources that directly support the material presented in an article and are appropriate to the claims made. The appropriateness of any source depends on the context. The best sources have a professional structure in place for checking or analyzing facts, legal issues, evidence, and arguments. The greater the degree of scrutiny given to these issues, the more reliable the source. Be especially careful when sourcing content related to living people or medicine.

If available, academic and peer-reviewed publications are usually the most reliable sources, such as in history, medicine, and science.

Editors may also use material from reliable non-academic sources, particularly if it appears in respected mainstream publications. Other reliable sources include:

university-level textbooks
books published by respected publishing houses
magazines
journals
mainstream newspapers.

Editors may also use electronic media, subject to the same criteria. See details in Wikipedia:Identifying reliable sources and Wikipedia:Search engine test.

https://en.wikipedia.org/wiki/Wikipedia:Verifiability