Tertiary sources present summaries or condensed versions of materials, usually with references back to the primary and/or secondary sources. They can be a good place to look up facts or get a general overview of a subject, but they rarely contain original material.
Examples: Dictionaries, Encyclopedias, Handbooks, Manuals
Secondary sources contain commentary on or discussion about primary sources. The most important feature of secondary sources is that they offer an interpretation of information gathered from primary sources.
Examples: Biographies, Dissertations, Indexes, Abstracts, Journal Articles, Books
Primary sources are original documents containing first-hand information about a topic. They allow researchers to get as close as possible to original ideas, events, and empirical research as possible. Such sources may include creative works, first hand or contemporary accounts of events, and the publication of the results of empirical observations or research.
Examples: Diaries, Interviews, Historical documents, Original Art, Photographs, Audio/Video recordings, works of literature
| Subject | Primary | Secondary | Tertiary |
|---|---|---|---|
| Art | Painting | Critical review of the painting | Encyclopedia article on the artist |
| History | Civil War diary | Book on a Civil War Battle | List of battle sites |
| Literature | Novel or poem | Essay about themes in the work | Biography of the author |
| Political science | Geneva Convention | Article about prisoners of war | Chronology of treaties |