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Primary, Secondary, and Tertiary Sources: Tertiary

Is a Source TERTIARY?

Sources that compile and summarize information on many different, conceptually-related topics, sources such as encyclopedias, almanacs, subject dictionaries, etc., are TERTIARY sources.

Google Scholar

Use Google Scholar to find academic-quality information (articles, papers, reports) on the Web.

Google Scholar Search

Tertiary Sources: A Closer Look

TERTIARY sources usually compile information on related topics in a single work, providing information at a glance, but usually not in any great depth. Tertiary sources typically draw from secondary, and sometimes from primary, sources.


  • The eminent Charles Darwin is discussed in many dictionaries and encyclopedias of famous scientists. These are tertiary sources.
  • The Oxford Dictionary of Scientists would be considered a tertiary source; you can view pages from it at Google Books.


A tertiary source summarizes information about a lot of different persons or subjects, like this dictionary of scientists.

Wikipedia and Encyclopedias

We will say one thing about encyclopedias, and Wikipedia in general:  NO.

Fifth grade should have been about the last time you dragged out the World Book, or any other encyclopedia, for academic research.  And there's a world of difference between the academic research you did for your state report back in elementary school and the research you're doing here.

Recreational research occupies a whole other realm of inquiry.  This is what we do when we want to know how many different  "Holy ---" epithets Robin has uttered over the entire Batman series or what a pomelo is.  For this kind of research, googling or just heading right over to Wikipedia is fine.

But it's not fine in this academic setting.  And while you can certainly dig through an article's reference list to see if any primary sources are consulted, it will be rare.  Your best bet is to stick with what is tried and true:

  • Search the CORE databases, specifying peer-reviewed works
  • Search any of the freely available online databases, which come from reputable sources like NIH or the NLM
  • Search your textbooks and consult their references.