Tier 1: most reliable[edit]

Peer-reviewed publications

Further information: List of academic databases and search engines and Lists of academic journals

Academic books

Further information: List of university presses

Tier 2: more reliable[edit]

Non-peer-reviewed academic publications

Mass-market books

Further information: List of English-language book publishing companies

Highly-reputable international journalism

Main page: WP:NEWSORG

Tier 3: reliable[edit]

Tertiary sources

Further information: Identifying and using tertiary sources (WP:TERTIARYUSE), Tertiary-source fallacy (WP:TSF), and Dictionaries as sources (WP:DICTS)

Other generally reliable news sources

Further information: WP:Reliable sources/Perennial sources and Otto Middleton (or why newspapers are dubious sources) (WP:OTTO)

Expert self-published

Tier 4: limited use[edit]

Non-expert self-published

Further information: Vanity and predatory publishing (WP:VANPRED) and WP:ABOUTSELF

Questionable sources

Further information: WP:Reliable sources/Perennial sources

Primary sources

Further information: Identifying and using primary sources (WP:USEPRIMARY)

See also[edit]

Policies
Guidelines
Explanatory supplements
General essays
Topic-specific essays
Other