MLA

Wescott, Glenway, 1901-1987. Moore, Mary Warner. Box 404, folder 4258. n.d.. https://collections.library.yale.edu/catalog/2000602.

APA, 6th edition

Wescott, Glenway, 1901-1987. (["Box 404, folder 4258"])(n.d.)[Moore, Mary Warner]. https://collections.library.yale.edu/catalog/2000602.