MLA

Hughes, Langston, 1902-1967. Abron, Adolph Jr.. Box 2, folder 20. 1951. https://collections.library.yale.edu/catalog/33086159.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 2, folder 20"])(1951)[Abron, Adolph Jr.]. https://collections.library.yale.edu/catalog/33086159.