MLA

Hughes, Langston, 1902-1967. Jackson, Marcus. Box 469, folder 11535. n.d.. https://collections.library.yale.edu/catalog/33549092.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 469, folder 11535"])(n.d.)[Jackson, Marcus]. https://collections.library.yale.edu/catalog/33549092.