MLA

Hughes, Langston, 1902-1967. Pitcher, Oliver. Box 129, folder 2423. 1949-65, n.d.. https://collections.library.yale.edu/catalog/17020447.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 129, folder 2423"])(1949-65, n.d.)[Pitcher, Oliver]. https://collections.library.yale.edu/catalog/17020447.