MLA

Van Vechten, Carl, 1880-1964. Jefferson, Louise E.. Box 94, folder 1661. 1964 February 4. https://collections.library.yale.edu/catalog/2001916.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 94, folder 1661"])(1964 February 4)[Jefferson, Louise E.]. https://collections.library.yale.edu/catalog/2001916.