Primary sources

• a first-hand account by a participant or observer close to the time of the event, as reported in an article, diary, journal, speech, interview, letter, e-mail, memorandum, or autobiography.
• an original work of art or literature
• visual images and/or audio recordings of an event
• old maps
• original research or raw data, including public opinion polls
• a government document that is produced in the normal course of governing (a law, congressional hearing, treaty, regulation or court decision) and those that record an event (birth certificate), report data collected by the government (the census), or confer a right (a permit, license or patent).
• records produced by organizations in the normal course of doing business
• a laboratory report or field observation, including an ethnography
• artifacts of any kind

Secondary Sources

• an analytical article or book about an event, including textbooks and encyclopedias
• an editorial
• a biography
• a documentary or reenactment
• reviews or literary criticism
• an article that describes or analyzes a third parties' research results
• a government report that analyzes events after-the-fact, relying on evidence collected or documents generated at the time of the event.  For example: United States.  National Aeronautics and Space Administration Office of Policy and Plans. Report of the Presidential Commission on the Space Shuttle Challenger Accident.  1986.
• a law review article or treatise on the law
• an interest group report criticizing the government's statistical analysis of census data
• a report examining the commercial viability of a particular enterprise by a consultant
• an article describing and analyzing the results of a third parties' work.

Combine these keywords with your search topic:

• sources [documents collected from multiple sources]
• archives [use for people or organizations]
• facsimiles
• correspondence [use with names of people, families, ethnic groups, organizations]
• description and travel [use with names of places]
• diaries [use with names or classes of people, ethnic groups, organizations]
• journals
• interviews [use with names or classes of people, ethnic groups, organizations]
• notebooks [use with names of people]
• speeches
• sermons
• pamphlets
• personal narratives [use only with armed conflicts or events]
• pictorial works
• posters
• photographs
• Press coverage
• caricatures and cartoons
• diplomatic history [used only with armed conflicts]
• treaties (used with subjects, geographic areas, ethnic groups, wars)
• maps