MLA

Koch, Frederick R. (Frederick Robinson). Music/Concerto, violoncello, orchestra. Box 336, folder 1953. [1955-56]. https://collections.library.yale.edu/catalog/2066428.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 336, folder 1953"])([1955-56])[Music/Concerto, violoncello, orchestra]. https://collections.library.yale.edu/catalog/2066428.