MLA

Koch, Frederick R. (Frederick Robinson). Sert, Misia. Box 55, folder 1218. 1919 Apr 27. https://collections.library.yale.edu/catalog/16601861.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 55, folder 1218"])(1919 Apr 27)[Sert, Misia]. https://collections.library.yale.edu/catalog/16601861.