MLA

McKay, Claude, 1890-1948. Typescript. Box 12, folder 363. n.d.. https://collections.library.yale.edu/catalog/32268800.

APA, 6th edition

McKay, Claude, 1890-1948. (["Box 12, folder 363"])(n.d.)[Typescript]. https://collections.library.yale.edu/catalog/32268800.