MLA

Hughes, Langston, 1902-1967. African Letters: O-Z. Box 223, folder 3700-3703. 1925-67, n.d.. https://collections.library.yale.edu/catalog/31916887.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 223, folder 3700-3703"])(1925-67, n.d.)[African Letters: O-Z]. https://collections.library.yale.edu/catalog/31916887.