MLA

Koch, Frederick R. (Frederick Robinson). Music/The Spitfire Prelude and Fugue: score. Box 340, folder 1988. [1942-43]. https://collections.library.yale.edu/catalog/2039600.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 340, folder 1988"])([1942-43])[Music/The Spitfire Prelude and Fugue: score]. https://collections.library.yale.edu/catalog/2039600.