MLA

Dreier, Katherine S. (Katherine Sophie), 1877-1952. "Portrait of Marcel Duchamp," pencil study. Box 76, folder 1980. n.d.. https://collections.library.yale.edu/catalog/2003478.

APA, 6th edition

Dreier, Katherine S. (Katherine Sophie), 1877-1952. (["Box 76, folder 1980"])(n.d.)["Portrait of Marcel Duchamp," pencil study]. https://collections.library.yale.edu/catalog/2003478.