MLA

Van Vechten, Carl, 1880-1964. Rubinstein, Artur. Box 373, folder 5348. 1937 November 30. https://collections.library.yale.edu/catalog/10033939.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 373, folder 5348"])(1937 November 30)[Rubinstein, Artur]. https://collections.library.yale.edu/catalog/10033939.