MLA

Pound, Ezra, 1885-1972. Marinetti, Filippo Tommaso. Box 33, folder 1377. 1932-44. https://collections.library.yale.edu/catalog/10756150.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 33, folder 1377"])(1932-44)[Marinetti, Filippo Tommaso]. https://collections.library.yale.edu/catalog/10756150.