MLA

Pound, Ezra, 1885-1972. Proof. Box 107, folder 4474. [1920]. https://collections.library.yale.edu/catalog/17122778.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 107, folder 4474"])([1920])[Proof]. https://collections.library.yale.edu/catalog/17122778.