MLA

McKay, Claude, 1890-1948. Draft, typescript. Box 12, folder 391. n.d.. https://collections.library.yale.edu/catalog/32269445.

APA, 6th edition

McKay, Claude, 1890-1948. (["Box 12, folder 391"])(n.d.)[Draft, typescript]. https://collections.library.yale.edu/catalog/32269445.