MLA

Koch, Frederick R. (Frederick Robinson). Music/Fantasio. Box 168, folder 1510. n.d.. https://collections.library.yale.edu/catalog/12189000.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 168, folder 1510"])(n.d.)[Music/Fantasio]. https://collections.library.yale.edu/catalog/12189000.