APA Citations (7th ed.)

A primary source reports original content.

A 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 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 Perry & Gossard (2021) in which Ulrich (2015) 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:

     (Ulrich, 2015, as cited in Perry & Gossard, 2021)

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)