MLA

Koch, Frederick R. (Frederick Robinson). Music/Absence. Box 159, folder 1501. n.d.. https://collections.library.yale.edu/catalog/12234903.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 159, folder 1501"])(n.d.)[Music/Absence]. https://collections.library.yale.edu/catalog/12234903.