MLA

Hughes, Langston, 1902-1967. American Negro Music Festival. Box 6, folder 133. 1944-45. https://collections.library.yale.edu/catalog/32579570.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 6, folder 133"])(1944-45)[American Negro Music Festival]. https://collections.library.yale.edu/catalog/32579570.