MLA

Levi, Ezio, 1884-1941. Unsorted. Box 5, folder 63-64. 1916-1943, undated. https://collections.library.yale.edu/catalog/17301344.

APA, 6th edition

Levi, Ezio, 1884-1941. (["Box 5, folder 63-64"])(1916-1943, undated)[Unsorted]. https://collections.library.yale.edu/catalog/17301344.