"Quoted in"
To cite a source from a secondary source is generally discouraged, since writers are supposed to have consulted the works they cite. If the original source is unavailable, and "quoted in" must be resorted to, mention the original author and date in the text, and cite the secondary source in the reference list entry. The text citation would include the words "quoted in."
For example:
In text
In Louis Zukofsky's "Sincerity and Objectification," from the February 1931 issue of Poetry magazine (quoted in Costello 1981)....
Reference list
Costello, Bonnie. 1981. Marianne Moore: Imaginary Possessions. Cam bridge, MA: Harvard University Press.
