MLA

Hughes, Langston, 1902-1967. Gibson, Althea. Box 468, folder 11470. n.d.. https://collections.library.yale.edu/catalog/17034169.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 468, folder 11470"])(n.d.)[Gibson, Althea]. https://collections.library.yale.edu/catalog/17034169.