MLA

Van Vechten, Carl, 1880-1964. Showers, Louis Upton. Box 104, folder 1897. 1934 September 19. https://collections.library.yale.edu/catalog/2027871.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 104, folder 1897"])(1934 September 19)[Showers, Louis Upton]. https://collections.library.yale.edu/catalog/2027871.