MLA

Dreier, Katherine S. (Katherine Sophie), 1877-1952. Rosenberg, Léonce. Box 30, folder 886. 1922-30. https://collections.library.yale.edu/catalog/17414353.

APA, 6th edition

Dreier, Katherine S. (Katherine Sophie), 1877-1952. (["Box 30, folder 886"])(1922-30)[Rosenberg, Léonce]. https://collections.library.yale.edu/catalog/17414353.