MLA

Van Vechten, Carl, 1880-1964. Ford, Ruth. Box 348, folder 4606-4607. 1939 June 9. https://collections.library.yale.edu/catalog/2034680.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 348, folder 4606-4607"])(1939 June 9)[Ford, Ruth]. https://collections.library.yale.edu/catalog/2034680.