MLA

Van Vechten, Carl, 1880-1964. Muschenheim, Ronda Keane Gould. Box 369, folder 5208. 1941 April 23. https://collections.library.yale.edu/catalog/2054758.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 369, folder 5208"])(1941 April 23)[Muschenheim, Ronda Keane Gould]. https://collections.library.yale.edu/catalog/2054758.