MLA

Hughes, Langston, 1902-1967. Hansberry, Lorraine. Box 74, folder 1426. 1958-64, n.d.. https://collections.library.yale.edu/catalog/16998772.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 74, folder 1426"])(1958-64, n.d.)[Hansberry, Lorraine]. https://collections.library.yale.edu/catalog/16998772.