MLA

Van Vechten, Carl, 1880-1964. Hammond, Natalie Hays. Box 352 | Folder 4717. 1944 October 4. https://collections.library.yale.edu/catalog/2036277.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 352 | Folder 4717"])(1944 October 4)[Hammond, Natalie Hays]. https://collections.library.yale.edu/catalog/2036277.