MLA

Pforzheimer, Walter L. (Walter Lionel), 1914-2003. "Christmas Eve" for St. Nicholas; watercolor on paper mounted on illustration board. Box 13, folder 112. 1894. https://collections.library.yale.edu/catalog/12332343.

APA, 6th edition

Pforzheimer, Walter L. (Walter Lionel), 1914-2003. (["Box 13, folder 112"])(1894)["Christmas Eve" for St. Nicholas; watercolor on paper mounted on illustration board]. https://collections.library.yale.edu/catalog/12332343.