MLA

Koch, Frederick R. (Frederick Robinson). Music/Unidentified/Orchestra music, scherzo. Box 345, folder 2049. n.d.. https://collections.library.yale.edu/catalog/2043679.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 345, folder 2049"])(n.d.)[Music/Unidentified/Orchestra music, scherzo]. https://collections.library.yale.edu/catalog/2043679.