MLA

Van Vechten, Carl, 1880-1964. Mitchell, Arthur. Box 99 | Folder 1766. 1955 December 20. https://collections.library.yale.edu/catalog/2026891.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 99 | Folder 1766"])(1955 December 20)[Mitchell, Arthur]. https://collections.library.yale.edu/catalog/2026891.