MLA

Koch, Frederick R. (Frederick Robinson). Music/Madame Favart. Box 329, folder 1837. [ca. 1878]. https://collections.library.yale.edu/catalog/12218307.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 329, folder 1837"])([ca. 1878])[Music/Madame Favart]. https://collections.library.yale.edu/catalog/12218307.