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How to Evaluate Information Sources: What Are Tertiary Sources?

Tertiary Sources

Tertiary sources of information are based on a collection of primary and secondary sources. Examples of tertiary sources include:

  • textbooks (sometimes considered as secondary sources)
  • dictionaries and encyclopedias
  • manuals, guidebooks, directories, almanacs
  • indexes and bibliographies

TIP:  What is considered primary, secondary, or tertiary information may vary according to your field of study. When in doubt, ask your professor.