MLA

Pound, Ezra, 1885-1972. Berti, Luigi. Box 4, folder 167-168. 1940-43. https://collections.library.yale.edu/catalog/2042132.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 4, folder 167-168"])(1940-43)[Berti, Luigi]. https://collections.library.yale.edu/catalog/2042132.