MLA

Hughes, Langston, 1902-1967. Clark, Carolyn. Box 456, folder 11027. 1916, 1929, n.d.. https://collections.library.yale.edu/catalog/2014043.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 456, folder 11027"])(1916, 1929, n.d.)[Clark, Carolyn]. https://collections.library.yale.edu/catalog/2014043.