MLA

Koch, Frederick R. (Frederick Robinson). Music/Chanson slave. Box 319, folder 1689. 1879 Oct 25. https://collections.library.yale.edu/catalog/17473502.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 319, folder 1689"])(1879 Oct 25)[Music/Chanson slave]. https://collections.library.yale.edu/catalog/17473502.