MLA

Hughes, Langston, 1902-1967. Allen, Alvan. Box 5, folder 98. 1957. https://collections.library.yale.edu/catalog/33090423.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 5, folder 98"])(1957)[Allen, Alvan]. https://collections.library.yale.edu/catalog/33090423.