MLA

Van Vechten, Carl, 1880-1964. Martin, Nan. Box 366, folder 5124. 1963 January 15. https://collections.library.yale.edu/catalog/2066609.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 366, folder 5124"])(1963 January 15)[Martin, Nan]. https://collections.library.yale.edu/catalog/2066609.