MLA

Van Vechten, Carl, 1880-1964. Curtis, Robert. Box 88, folder 1499. 1955 April 19. https://collections.library.yale.edu/catalog/2022015.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 88, folder 1499"])(1955 April 19)[Curtis, Robert]. https://collections.library.yale.edu/catalog/2022015.