MLA

Hughes, Langston, 1902-1967. Leon, Maria Teresa. Box 469, folder 11575. n.d.. https://collections.library.yale.edu/catalog/33548816.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 469, folder 11575"])(n.d.)[Leon, Maria Teresa]. https://collections.library.yale.edu/catalog/33548816.