Cite

Music/Unidentified/Orchestra music, theme and variations

MLA

Koch, Frederick R. (Frederick Robinson). Music/Unidentified/Orchestra music, theme and variations. Box 345, folder 2050. n.d.. https://collections.library.yale.edu/catalog/2043680.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 345, folder 2050"])(n.d.)[Music/Unidentified/Orchestra music, theme and variations]. https://collections.library.yale.edu/catalog/2043680.