MLA

Van Vechten, Carl, 1880-1964. Bishop, John Peale. Box 336, folder 4247. 1941 March 18. https://collections.library.yale.edu/catalog/2030846.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 336, folder 4247"])(1941 March 18)[Bishop, John Peale]. https://collections.library.yale.edu/catalog/2030846.