MLA

Butts, Mary, 1890-1937. "To Anthony Butts," typescript carbon. Box 5, folder 87. n.d.. https://collections.library.yale.edu/catalog/31908810.

APA, 6th edition

Butts, Mary, 1890-1937. (["Box 5, folder 87"])(n.d.)["To Anthony Butts," typescript carbon]. https://collections.library.yale.edu/catalog/31908810.