MLA

Van Vechten, Carl, 1880-1964. Shaffer, Susan Angevine. Box 375, folder 5410. 1936 February 27. https://collections.library.yale.edu/catalog/10054005.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 375, folder 5410"])(1936 February 27)[Shaffer, Susan Angevine]. https://collections.library.yale.edu/catalog/10054005.