MLA

Pound, Ezra, 1885-1972. "Black List": typescript. Box 129, folder 5367. [1941 Jul 22]. https://collections.library.yale.edu/catalog/10034809.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 129, folder 5367"])([1941 Jul 22])["Black List": typescript]. https://collections.library.yale.edu/catalog/10034809.