MLA

Koch, Frederick R. (Frederick Robinson). Writings/Tropic of Cancer, volume 1. Box 154, folder 1496. [ca. 1930-32]. https://collections.library.yale.edu/catalog/2005946.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 154, folder 1496"])([ca. 1930-32])[Writings/Tropic of Cancer, volume 1]. https://collections.library.yale.edu/catalog/2005946.