MLA

Koch, Frederick R. (Frederick Robinson). Music/Sicilian mariner's hymn. Box 322, folder 1742. n.d.. https://collections.library.yale.edu/catalog/2007268.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 322, folder 1742"])(n.d.)[Music/Sicilian mariner's hymn]. https://collections.library.yale.edu/catalog/2007268.