MLA

Van Vechten, Carl, 1880-1964. Perényi, Peter. Box 370, folder 5265. 1946 January 5. https://collections.library.yale.edu/catalog/10000632.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 370, folder 5265"])(1946 January 5)[Perényi, Peter]. https://collections.library.yale.edu/catalog/10000632.