MLA

Van Vechten, Carl, 1880-1964. Hawkins, William. Box 353, folder 4740. 1938 December 16. https://collections.library.yale.edu/catalog/2036521.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 353, folder 4740"])(1938 December 16)[Hawkins, William]. https://collections.library.yale.edu/catalog/2036521.