MLA

Thurman, Wallace, 1902-1934. Rapp, William Jourdan. Box 1, folder 7-8. 1928, 1929, n.d.. https://collections.library.yale.edu/catalog/2013648.

APA, 6th edition

Thurman, Wallace, 1902-1934. (["Box 1, folder 7-8"])(1928, 1929, n.d.)[Rapp, William Jourdan]. https://collections.library.yale.edu/catalog/2013648.