MLA

Dreier, Katherine S. (Katherine Sophie), 1877-1952. Mission statements, typescript and carbon, corrected. Box 93, folder 2360. n.d.. https://collections.library.yale.edu/catalog/32209656.

APA, 6th edition

Dreier, Katherine S. (Katherine Sophie), 1877-1952. (["Box 93, folder 2360"])(n.d.)[Mission statements, typescript and carbon, corrected]. https://collections.library.yale.edu/catalog/32209656.