You read a book by Costello that cites an earlier article by Zukofsky. You want to cite Zukofsky's article, but have not read Zukofsky's article itself.
Note:
7. Louis Zukofsky, "Sincerity and Objectification," Poetry 37 (February 1931):269, quoted in Bonnie Costello, Marianne Moore: Imaginary Possessions (Cambridge, MA: Harvard University Press, 1981), 78.
Bibliographic entry:
Zukofsky, Louis."Sincerity and Objectification." Poetry 37 (February 1931):269. Quoted in Bonnie Costello, Marianne Moore: Imaginary Possessions. Cambridge, MA: Harvard University Press, 1981, 78.