MLA

Hughes, Langston, 1902-1967. Abraham Lincoln Brigade. Box 2, folder 16. 1938-66. https://collections.library.yale.edu/catalog/32604020.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 2, folder 16"])(1938-66)[Abraham Lincoln Brigade]. https://collections.library.yale.edu/catalog/32604020.