MLA

Pound, Ezra, 1885-1972. Crowder, Henry. Box 10, folder 477. 1929. https://collections.library.yale.edu/catalog/17122543.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 10, folder 477"])(1929)[Crowder, Henry]. https://collections.library.yale.edu/catalog/17122543.