MLA

Meserve, Frederick Hill, 1865-1962. Thompson, George W., 1836-1901, as a character in an unidentified theatrical production. Box 166, folder 12613. approximately 1865. https://collections.library.yale.edu/catalog/16198651.

APA, 6th edition

Meserve, Frederick Hill, 1865-1962. (["Box 166, folder 12613"])(approximately 1865)[Thompson, George W., 1836-1901, as a character in an unidentified theatrical production]. https://collections.library.yale.edu/catalog/16198651.