MLA

Koch, Frederick R. (Frederick Robinson). Bristow, Anne. Box 1, folder 4-5. 1930-32. https://collections.library.yale.edu/catalog/2000051.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 1, folder 4-5"])(1930-32)[Bristow, Anne]. https://collections.library.yale.edu/catalog/2000051.