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APA Citations (7th ed.): Secondary Sources

This guide will help you learn how to properly cite sources in APA style and how to avoid plagiarism.

What is a Secondary Source?

A primary source reports original content.

secondary source refers to content first reported in another source.

It is preferred to cite primary sources. You should cite secondary sources when:

  • The original work is out of print or unavailable
  • The original work is only available in a language you do not understand
  • You are not able to locate the original work

To learn more about citing secondary sources, see p. 258 of the manual.


How to Cite Secondary Sources

To cite a secondary source:

  • Provide a reference list entry for the secondary source you are citing.
  • In the text, identify the primary source and then write "as cited in" the secondary source that you used.
  • If the year of publication is known for the primary source, also include it in the text.


Say you read an article by Knipe & Horowitz (2018) in which Truslow (2009) was cited. You are unable to read Truslow's work yourself. The reference list would only include the secondary source by Knipe & Horowitz (2018). The in-text citation would look as it does below:

In-text citation:

     (Truslow, 2009, as cited in Knipe & Horowitz, 2018)

Unknown Year, Primary Source

If the year of the primary source is unknown, omit it from the in-text citation.

In-text citation:

     Newton's diary (as cited in Hale, 1912)