MLA

Koch, Frederick R. (Frederick Robinson). Music/Madame l'archiduc. Box 329, folder 1838. 1874 Jun 28. https://collections.library.yale.edu/catalog/12218308.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 329, folder 1838"])(1874 Jun 28)[Music/Madame l'archiduc]. https://collections.library.yale.edu/catalog/12218308.