MLA

Pound, Ezra, 1885-1972. "America Seeing Snakes": typescript. Box 128, folder 5320. [1942?]. https://collections.library.yale.edu/catalog/10034691.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 128, folder 5320"])([1942?])["America Seeing Snakes": typescript]. https://collections.library.yale.edu/catalog/10034691.