MLA

Hughes, Langston, 1902-1967. Louis, Joe. Box 7 (Oversize), folder 82. 1941, undated. https://collections.library.yale.edu/catalog/16198530.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 7 (Oversize), folder 82"])(1941, undated)[Louis, Joe]. https://collections.library.yale.edu/catalog/16198530.