MLA

Van Vechten, Carl, 1880-1964. Kay, Ulysses. Box 95, folder 1684. 1946 May 23. https://collections.library.yale.edu/catalog/2025770.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 95, folder 1684"])(1946 May 23)[Kay, Ulysses]. https://collections.library.yale.edu/catalog/2025770.