MLA

Van Vechten, Carl, 1880-1964. Servoss, Mary. Box 375, folder 5397. 1932 September 21. https://collections.library.yale.edu/catalog/10052333.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 375, folder 5397"])(1932 September 21)[Servoss, Mary]. https://collections.library.yale.edu/catalog/10052333.