MLA

Van Vechten, Carl, 1880 - 1964. Sandiford, Frank. Box 374 | Folder 5370. 1951 April 25. https://collections.library.yale.edu/catalog/10050782.

APA, 6th edition

Van Vechten, Carl, 1880 - 1964. (["Box 374 | Folder 5370"])(1951 April 25)[Sandiford, Frank]. https://collections.library.yale.edu/catalog/10050782.