MLA

Hughes, Langston, 1902-1967. Ballard, George. Box 19, folder 235. 1875-1978. https://collections.library.yale.edu/catalog/16207016.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 19, folder 235"])(1875-1978)[Ballard, George]. https://collections.library.yale.edu/catalog/16207016.