MLA

Van Vechten, Carl, 1880-1964. Jackson, Mahalia. Box 94, folder 1656. 1962 April 16. https://collections.library.yale.edu/catalog/2001915.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 94, folder 1656"])(1962 April 16)[Jackson, Mahalia]. https://collections.library.yale.edu/catalog/2001915.