MLA

Pound, Ezra, 1885-1972. Carnevali, Emanuel. Box 3, folder 72. [1930?]. https://collections.library.yale.edu/catalog/10280400.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 3, folder 72"])([1930?])[Carnevali, Emanuel]. https://collections.library.yale.edu/catalog/10280400.