MLA

Dreier, Katherine S. (Katherine Sophie), 1877-1952. Marcoussis, Louis. Box 23, folder 675. 1927, n.d.. https://collections.library.yale.edu/catalog/16694419.

APA, 6th edition

Dreier, Katherine S. (Katherine Sophie), 1877-1952. (["Box 23, folder 675"])(1927, n.d.)[Marcoussis, Louis]. https://collections.library.yale.edu/catalog/16694419.