MLA

Hughes, Langston, 1902-1967. Essay by Langston Hughes: "Black Writers in a Troubled World", mimeograph copy, corrected. Box 582, folder 13863. n.d.. https://collections.library.yale.edu/catalog/17034224.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 582, folder 13863"])(n.d.)[Essay by Langston Hughes: "Black Writers in a Troubled World", mimeograph copy, corrected]. https://collections.library.yale.edu/catalog/17034224.