MLA

Koch, Frederick R. (Frederick Robinson). Music/Mailied. Box 342, folder 2014. n.d.. https://collections.library.yale.edu/catalog/2043664.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 342, folder 2014"])(n.d.)[Music/Mailied]. https://collections.library.yale.edu/catalog/2043664.