MLA

Pound, Ezra, 1885-1972. Fitzgerald, Desmond. Box 16, folder 733. 1926-39. https://collections.library.yale.edu/catalog/17122560.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 16, folder 733"])(1926-39)[Fitzgerald, Desmond]. https://collections.library.yale.edu/catalog/17122560.