MLA

Dreier, Katherine S. (Katherine Sophie), 1877-1952. Lissitzky-Küppers, Sophie. Box 22, folder 635. 1926-27. https://collections.library.yale.edu/catalog/16694418.

APA, 6th edition

Dreier, Katherine S. (Katherine Sophie), 1877-1952. (["Box 22, folder 635"])(1926-27)[Lissitzky-Küppers, Sophie]. https://collections.library.yale.edu/catalog/16694418.