MLA

Blumer, George (1872-1962). Two Stethoscopes Wooden. Box 099. ca. 19th century. https://collections.library.yale.edu/catalog/17321852.

APA, 6th edition

Blumer, George (1872-1962). (["Box 099"])(ca. 19th century)[Two Stethoscopes Wooden]. https://collections.library.yale.edu/catalog/17321852.