MLA

Erdoes, Richard, 1912-2008. "Amphitheater, Natural". Box 83. 1975-1988. https://collections.library.yale.edu/catalog/2104321.

APA, 6th edition

Erdoes, Richard, 1912-2008. (["Box 83"])(1975-1988)["Amphitheater, Natural"]. https://collections.library.yale.edu/catalog/2104321.