MLA

Dreier, Katherine S. (Katherine Sophie), 1877-1952. "Fresh Widow". Box 73, folder 1903. n.d.. https://collections.library.yale.edu/catalog/2017789.

APA, 6th edition

Dreier, Katherine S. (Katherine Sophie), 1877-1952. (["Box 73, folder 1903"])(n.d.)["Fresh Widow"]. https://collections.library.yale.edu/catalog/2017789.