MLA

Pound, Ezra, 1885-1972. Typescript, corrected. Box 31, folder 702. n.d.. https://collections.library.yale.edu/catalog/2055102.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 31, folder 702"])(n.d.)[Typescript, corrected]. https://collections.library.yale.edu/catalog/2055102.