MLA

Koch, Frederick R. (Frederick Robinson). Music/Crown Imperial: short score. Box 337, folder 1955. n.d.. https://collections.library.yale.edu/catalog/2067445.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 337, folder 1955"])(n.d.)[Music/Crown Imperial: short score]. https://collections.library.yale.edu/catalog/2067445.