MLA

Koch, Frederick R. (Frederick Robinson). Music/The Promised Land: score. Box 193, folder 1535. n.d.. https://collections.library.yale.edu/catalog/10518919.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 193, folder 1535"])(n.d.)[Music/The Promised Land: score]. https://collections.library.yale.edu/catalog/10518919.