MLA

Koch, Frederick R. (Frederick Robinson). Music/Neig schöne Knospe. Box 342, folder 2015. n.d.. https://collections.library.yale.edu/catalog/2043665.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 342, folder 2015"])(n.d.)[Music/Neig schöne Knospe]. https://collections.library.yale.edu/catalog/2043665.