MLA

Van Vechten, Carl, 1880-1964. Van Vechten, Carl. Box 497, folder 8867. 1943 September 25. https://collections.library.yale.edu/catalog/2002538.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 497, folder 8867"])(1943 September 25)[Van Vechten, Carl]. https://collections.library.yale.edu/catalog/2002538.