"American mixture of the Ethiopian race."
MLA
Bell, Mary A., 1873-1941. "American mixture of the Ethiopian race.". Box 1 (Oversize), folder 1. [1936-1939]. https://collections.library.yale.edu/catalog/2003123.
APA, 6th edition
Bell, Mary A., 1873-1941. (["Box 1 (Oversize), folder 1"])([1936-1939])["American mixture of the Ethiopian race."]. https://collections.library.yale.edu/catalog/2003123.