MLA

Koch, Frederick R. (Frederick Robinson). Music/Lutter, aimer. Box 322, folder 1741. [ca. 1880?]. https://collections.library.yale.edu/catalog/2007260.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 322, folder 1741"])([ca. 1880?])[Music/Lutter, aimer]. https://collections.library.yale.edu/catalog/2007260.