MLA

Hughes, Langston, 1902-1967. Buck, Gene. Box 17, folder 197. 1937. https://collections.library.yale.edu/catalog/16847708.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 17, folder 197"])(1937)[Buck, Gene]. https://collections.library.yale.edu/catalog/16847708.