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Finding Primary, Secondary, & Tertiary Sources

tips for searching and evaluating

Finding primary sources at CMU

Using OneSearch

  • OneSearch is the "automatic" (already chosen) way to search on the library home page. Using it, you will access a wide variety of the sources available through Tomlinson Library. In the left menu, under source type, your search will sometimes net primary source documents. By choosing to limit to these, you can evaluate them according to what you learn in class and from this guide to see if you agree with the label in the context of your assignment.
  • Hint: this doesn't mean that the search has discovered all of the primary sources for you. Check under the source types academic journals, audio, books, conference materials, dissertations/theses, maps, music scores, reports, and videos (depending on your subject area), as well.

Special Collections & Archives

  • Primary Source materials are pretty much the business of the Special Collections & Archives department of the library, located on the 3rd floor. Documents related to Colorado history, the Department of Energy, and the history of CMU are just some of what you find by through the library search and by visiting, There are also archival documents and photos available through the Digital Collections of Colorado.

Three Degrees of Separation

When you are trying to identify primary sources, think first-hand, contemporary, direct evidence or data, original records, artwork, writing, or research. 

Hint: if someone is providing any kind of interpretation, summary, criticism, analysis, definition, or compilation of originals, you are probably straying into secondary or tertiary source territory!

Visualizing Primary Sources

Primary Sources: documents, audiovisual materials, objects or data sets created during the time under study. The viewpoint is from the inside.

Examples: Peer-reviewed articles/studies, transcripts, podcasts, musical scores, works of art and literature, interviews, artifacts, autobiographies/diaries, fossils, conference proceedings, specimens, eyewitness accounts, market surveys, data sets, photographs, government documents, websites, polls, television programs, tweets/posts/emails/texts.