APA recommends one avoid secondary sources when possible. However, if it is not possible to track down the original work, it is okay to cite a secondary source. (APA Style Blog, apastyle.org)
In Warkinton’s study (as cited in Roberts, Jones & Munroe, 2014), children’s cognitive growth and development …
Roberts, Jones & Munroe (2014) examined Warkinton’s study on children’s cognitive growth and development……
Roberts, M., Jones, R.L., & Munroe, N. (2014). Children and cognition and
the development of language. Psychological Reports, 19(7), 412-419.
In the text acknowledge the original work (e.g. Warkinton’s study). Provide a citation for the secondary source in the reference list. The secondary source is the source that you have (where you obtained your information). In the example above the secondary source is by Roberts, Jones & Munroe. Do NOT provide a citation for the original work in the reference list (e.g. Warkinton’s study). (Publication manual, 2010, p. 178)