Wikipedia talk:Attribution/Community discussion/transclusion/Reliable sources

Reliable sources

Primary and secondary sources

source: WP:NOR#Sources

For examples, see FAQ: Types of source material

Primary sources are documents or people very close to the situation being written about. An eyewitness account of a traffic accident is a primary source. The White House's summary of a president's speech is a primary source. Primary sources that have been published by a reliable source may be used in Wikipedia, but only with care, because it's easy to misuse them. For that reason, anyone—without specialist knowledge—who reads the primary source should be able to verify that the Wikipedia passage agrees with the primary source. Any interpretation of primary source material requires a secondary source.
Examples of primary sources include archeological artifacts; photographs; newspaper accounts which contain first-hand material, not merely analysis or commentary of other material; historical documents such as diaries, census results, video or transcripts of surveillance, public hearings, trials, or interviews; tabulated results of surveys or questionnaires; written or recorded notes of laboratory and field experiments or observations; and artistic and fictional works such as poems, scripts, screenplays, novels, motion pictures, videos, and television programs.

Secondary sources draw on primary sources in order to make generalizations or original interpretive, analytical, synthetic, or explanatory claims. A journalist's analysis or commentary of a traffic accident based on eye-witness reports is a secondary source. A New York Times analysis and commentary on a president's speech is a secondary source. An historian's interpretation of the decline of the Roman Empire, or analysis of the historical Jesus, constitute secondary sources. Wikipedia articles should rely on reliable, verifiable, published secondary sources wherever possible. This means that we present verifiable accounts of views and arguments of reliable scholars, and not interpretations of primary source material by Wikipedians.

Using questionable or self-published sources

source: WP:V#Sources

Some sources pose special difficulties:

A questionable source is one with no editorial oversight or fact-checking process or with a poor reputation for fact-checking. Such sources include websites and publications that express views that are widely acknowledged as fringe or extremist, are promotional in nature, or rely heavily on rumors and personal opinions. Questionable sources may only be used in articles about themselves.
A self-published source is material that has been published by the author, or whose publisher is a vanity press, a web-hosting service, or other organization that provides little or no editorial oversight. Personal websites and messages either on USENET or on Internet bulletin boards are considered self-published. With self-published sources, no one stands between the author and publication; the material may not be subject to any form of fact-checking, legal scrutiny, or peer review. Anyone can create a website or pay to have a book published and then claim to be an expert in a certain field; visiting a stranger's personal website is often the online equivalent of reading an unattributed flyer on a lamp post. For that reason, self-published material is largely not acceptable.

There are two exceptions:

1. Self-published and questionable sources in articles about themselves

Material from self-published or questionable sources may be used in articles about those sources, so long as:

it is relevant to their notability;
it is not contentious;
it is not unduly self-serving;
it does not involve claims about third parties, or about events not directly related to the subject;
there is no reasonable doubt as to who wrote it;
the article is not based primarily on such sources.

2. Professional self-published sources: When a well-known, professional researcher writing within his or her field of expertise has produced self-published material, these may be acceptable as sources, so long as his or her work has been previously published by reliable, third-party publications. Editors should exercise caution for two reasons: first, if the information on the professional researcher's blog (or self-published equivalent) is really worth reporting, a reliable source will probably have covered it; secondly, the information has been self-published, which means it has not been subject to independent fact-checking. Self-published sources, such as personal websites and blogs, must never be used as third-party sources about living persons, even if the author is a well-known professional researcher or writer; see WP:BLP. If a third-party source has published the same or substantially similar material, that source should be used in preference to the self-published one.

Exceptional claims require exceptional sources

source: WP:RS#Exceptional claims require exceptional sources

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

surprising or apparently important claims that are not widely known;
surprising or apparently important reports of recent events not covered by reliable news media;
reports of a statement by someone that seems out of character, embarrassing, controversial, or against an interest they had previously defended;
claims not supported or claims that are contradicted by the prevailing view in the relevant academic community. Be particularly careful when proponents of such claims say there is a conspiracy to silence them.

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

Citing yourself

source: WP:NOR#Citing oneself

.

You may cite your own publications just as you would cite anyone else's, but make sure your material is relevant and that you are regarded as a reliable source for the purposes of Wikipedia. Be cautious about excessive citation of your own work, which may be seen as promotional or a conflict of interest; when in doubt, check on the talk page.

Language

source: WP:V#Sources in languages other than English

Because this is the English Wikipedia, for the convenience of our readers, English-language sources should be used in preference to foreign-language sources provided they are otherwise of equal suitability, so that readers can easily verify that the source material has been used correctly. Published translations are preferred to editors' translations; when editors use their own translations, the original-language material should be provided too, preferably in a footnote, so that readers can check the translation for themselves.