MLA

Pound, Ezra, 1885-1972. Wheeler, Burton Kendall. Box 55, folder 2502. 1936-40. https://collections.library.yale.edu/catalog/17122648.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 55, folder 2502"])(1936-40)[Wheeler, Burton Kendall]. https://collections.library.yale.edu/catalog/17122648.