MLA

Benét, Stephen Vincent, 1898-1943. Prince, William Meade. Box 24, folder 978. 1929 January 14. https://collections.library.yale.edu/catalog/17063398.

APA, 6th edition

Benét, Stephen Vincent, 1898-1943. (["Box 24, folder 978"])(1929 January 14)[Prince, William Meade]. https://collections.library.yale.edu/catalog/17063398.