MLA

Sanborn Map Company, issuing body. Watertown, Litchfield County, Conn. 1911. https://collections.library.yale.edu/catalog/11676458.

APA, 6th edition

Sanborn Map Company, issuing body. (1911). Watertown, Litchfield County, Conn. [Atlases--Connecticut--Watertown--1911, Cadastral maps--Connecticut--Watertown--1911, Fire insurance maps--Connecticut--Watertown--1911]. https://collections.library.yale.edu/catalog/11676458.