MLA

Hughes, Langston, 1902-1967. Adams, Harriett. Box 2, folder 30-33. 1963-66, n.d.. https://collections.library.yale.edu/catalog/32604638.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 2, folder 30-33"])(1963-66, n.d.)[Adams, Harriett]. https://collections.library.yale.edu/catalog/32604638.