In general, for all formats:
For books:
What evidence of research is provided? Look for references or a bibliography / works cited, endnotes or footnotes.
Have book reviews indicated that the book offers accurate, reliable information?
For periodical articles:
What evidence of research is provided? Look for references or a bibliography / works cited, endnotes or footnotes.
Is there evidence of bias or propaganda? (See the Purpose guide for more details)
Did the article undergo peer review?
For websites:
What other sites have links back to this site? Using Google, type in “link:” immediately followed by the website address.
Is the website well-organized and easy to navigate?
What are the author(s) research methods?