MLA

Van Vechten, Carl, 1880-1964. Clay, Omar. Box 87, folder 1470. 1962 October 30. https://collections.library.yale.edu/catalog/2021808.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 87, folder 1470"])(1962 October 30)[Clay, Omar]. https://collections.library.yale.edu/catalog/2021808.