For sources that you have not actually seen (the primary source) but that are referred to in another work (the secondary source):
For example, if Bennett’s work is cited in a book by Stone (2013) that you read, and you haven’t read Bennett’s original work, list the book you have read in the reference list.
Stone, R. J. (2013). Managing human resources (4th ed.). Wiley.
Bennett (2001, as cited in Stone, 2013, p. 176) defined ... OR
Research indicates ... (Bennett, 2001, as cited in Stone, 2013, p. 176)
If the year of the primary source is unknown, omit it from the in-text citation, for example
Bennett (as cited in Stone, 2013, p. 176) defined ... OR
Research indicates ... (Bennett, as cited in Stone, 2013, p. 176).
Cite secondary sources sparingly – for instance, when the original work is out of print, unavailable or only available in a language you don’t understand.
