MLA

Van Vechten, Carl, 1880-1964. Barr, Richard. Box 334, folder 4197. 1959 October 20. https://collections.library.yale.edu/catalog/2030468.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 334, folder 4197"])(1959 October 20)[Barr, Richard]. https://collections.library.yale.edu/catalog/2030468.