MLA

Matthiessen, F. O. (Francis Otto), 1902-1950. MacLeish, Archibald. Box 3. 1939-1945. https://collections.library.yale.edu/catalog/32239732.

APA, 6th edition

Matthiessen, F. O. (Francis Otto), 1902-1950. (["Box 3"])(1939-1945)[MacLeish, Archibald]. https://collections.library.yale.edu/catalog/32239732.