MLA

Pound, Ezra, 1885-1972. Quinn, John. Box 43, folder 1813-1825. 1915-20, n.d.. https://collections.library.yale.edu/catalog/17122617.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 43, folder 1813-1825"])(1915-20, n.d.)[Quinn, John]. https://collections.library.yale.edu/catalog/17122617.