MLA

Erdoes, Richard, 1912-2008. "Horse Surgery, Medium". Box 61. 1977. https://collections.library.yale.edu/catalog/2088465.

APA, 6th edition

Erdoes, Richard, 1912-2008. (["Box 61"])(1977)["Horse Surgery, Medium"]. https://collections.library.yale.edu/catalog/2088465.