MLA

Wescott, Glenway, 1901-1987. McAndrew, John. Box 403, folder 4241. n.d.. https://collections.library.yale.edu/catalog/17065039.

APA, 6th edition

Wescott, Glenway, 1901-1987. (["Box 403, folder 4241"])(n.d.)[McAndrew, John]. https://collections.library.yale.edu/catalog/17065039.