MLA

Hughes, Langston, 1902-1967. Rive, Richard. Box 471, folder 11666. 1955, n.d.. https://collections.library.yale.edu/catalog/2017012.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 471, folder 11666"])(1955, n.d.)[Rive, Richard]. https://collections.library.yale.edu/catalog/2017012.