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Primary, Secondary, and Tertiary Sources

Learn to distinguish primary, secondary and tertiary sources in the humanities and sciences.

What are tertiary sources?

Tertiary sources provide analysis of an event or idea, similar to secondary sources. Tertiary sources differ from secondary sources, however, because they are intended to be a broad overview that introduces a topic without providing the depth of analysis typically found in secondary sources.  

Tertiary sources compile and distil information taken from either primary or secondary sources or even a combination of both. The most common types of tertiary sources are dictionaries and encyclopedias.  For example, the Encyclopedia of American Studies contains an entry for the Declaration of Independence. This entry provides an overview of the document: who wrote it, who signed it, what ideas it communicated, etc.  This type of entry would be useful for someone who needed basic information about the Declaration of Independence.

Use the tabs below to view examples of tertiary sources in both the Humanities and Sciences.


To cite this LibGuide use the following templates:

APA: Northern Essex Community College Library. (Date updated). Title of page. Title of LibGuide. URL

MLA: Northern Essex Community College Library. "Title of Page." Title of LibGuide, Date updated, URL.