MLA

Pound, Ezra, 1885-1972. Letters. Box 63, folder 2764-2765. 1960. https://collections.library.yale.edu/catalog/32161158.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 63, folder 2764-2765"])(1960)[Letters]. https://collections.library.yale.edu/catalog/32161158.