MLA

Van Vechten, Carl, 1880-1964. Locher, Robert Evans. Box 362, folder 4999. 1937 July 22. https://collections.library.yale.edu/catalog/2056511.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 362, folder 4999"])(1937 July 22)[Locher, Robert Evans]. https://collections.library.yale.edu/catalog/2056511.