MLA

Van Vechten, Carl, 1880-1964. Warfield, William. Box 149, folder 2831. 1954 May 25. https://collections.library.yale.edu/catalog/33288477.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 149, folder 2831"])(1954 May 25)[Warfield, William]. https://collections.library.yale.edu/catalog/33288477.