MLA

Pound, Ezra, 1885-1972. Stafford, J. Richard. Box 49, folder 2189-2190. 1956-60. https://collections.library.yale.edu/catalog/17122631.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 49, folder 2189-2190"])(1956-60)[Stafford, J. Richard]. https://collections.library.yale.edu/catalog/17122631.