MLA

Jolas, Eugène, 1894-1952. Ungaretti, Giuseppe. Box 37, folder 801. n.d.. https://collections.library.yale.edu/catalog/17337764.

APA, 6th edition

Jolas, Eugène, 1894-1952. (["Box 37, folder 801"])(n.d.)[Ungaretti, Giuseppe]. https://collections.library.yale.edu/catalog/17337764.