MLA

Van Vechten, Carl, 1880-1964. Janta, Aleksander. Box 355, folder 4800. 1938 April 21. https://collections.library.yale.edu/catalog/10050785.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 355, folder 4800"])(1938 April 21)[Janta, Aleksander]. https://collections.library.yale.edu/catalog/10050785.