MLA

Koch, Frederick R. (Frederick Robinson). Music/Le fifre enchanté: finale. Box 329, folder 1833. n.d.. https://collections.library.yale.edu/catalog/2018740.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 329, folder 1833"])(n.d.)[Music/Le fifre enchanté: finale]. https://collections.library.yale.edu/catalog/2018740.