MLA

Hughes, Langston, 1902-1967. Dover, Cedric; Dover, Dorothy. Box 56, folder 1059. 1946-62, n.d.. https://collections.library.yale.edu/catalog/16998758.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 56, folder 1059"])(1946-62, n.d.)[Dover, Cedric; Dover, Dorothy]. https://collections.library.yale.edu/catalog/16998758.