MLA

Van Vechten, Carl, 1880-1964. Flanner, Janet. Box 348 | Folder 4598. 1940 December 12. https://collections.library.yale.edu/catalog/2034648.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 348 | Folder 4598"])(1940 December 12)[Flanner, Janet]. https://collections.library.yale.edu/catalog/2034648.