MLA

Van Vechten, Carl, 1880-1964. Knopf, Blanche. Box 357 | Folder 4874. 1932 April 4. https://collections.library.yale.edu/catalog/2054926.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 357 | Folder 4874"])(1932 April 4)[Knopf, Blanche]. https://collections.library.yale.edu/catalog/2054926.