MLA

Dreier, Katherine S. (Katherine Sophie), 1877-1952. 8th, 1921 Mar 15-Apr 12. Flyer, drafts, typescript carbon and printed. Box 87, folder 2240. [1921]. https://collections.library.yale.edu/catalog/10159353.

APA, 6th edition

Dreier, Katherine S. (Katherine Sophie), 1877-1952. (["Box 87, folder 2240"])([1921])[8th, 1921 Mar 15-Apr 12. Flyer, drafts, typescript carbon and printed]. https://collections.library.yale.edu/catalog/10159353.