MLA

Van Vechten, Carl, 1880-1964. Wong, Richard. Box 384, folder 5733. 1940 September 13. https://collections.library.yale.edu/catalog/10646256.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 384, folder 5733"])(1940 September 13)[Wong, Richard]. https://collections.library.yale.edu/catalog/10646256.