MLA

Pound, Ezra, 1885-1972. Letters. Box 62, folder 2723-2726. 1950. https://collections.library.yale.edu/catalog/32160718.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 62, folder 2723-2726"])(1950)[Letters]. https://collections.library.yale.edu/catalog/32160718.