MLA

Van Vechten, Carl, 1880-1964. Hopper, Hedda. Box 353 | Folder 4760. 1934 October 18. https://collections.library.yale.edu/catalog/2001985.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 353 | Folder 4760"])(1934 October 18)[Hopper, Hedda]. https://collections.library.yale.edu/catalog/2001985.