In scholarly work, a primary source reports original content; a secondary source refers to content first reported in another source.
Secondary sources are covered in the seventh edition APA Style manuals in the Publication Manual Section 8.6 and the Concise Guide Section 8.6
This guidance has been expanded from the 6th edition.
Follow these directions when citing a secondary source:
If the year of publication of the primary source is known, also include it in the text citation.
For example, if you read a work by Lyon et al. (2014) in which Rabbitt (1982) was cited, and you were unable to read Rabbitt’s work yourself, cite Rabbitt’s work as the original source, followed by Lyon et al.’s work as the secondary source. Only Lyon et al.’s work appears in the reference list.
(Rabbitt, 1982, as cited in Lyon et al., 2014)
If the year of the primary source is unknown, omit it from the in-text citation.
Allport’s diary (as cited in Nicholson, 2003)