MLA

Sanborn-Perris Map Co., issuing body. New Milford, Litchfield County, Conn. 1897. https://collections.library.yale.edu/catalog/11551283.

APA, 6th edition

Sanborn-Perris Map Co., issuing body. (1897). New Milford, Litchfield County, Conn. [Atlases--Connecticut--New Milford--1897, Cadastral maps--Connecticut--New Milford--1897, Fire insurance maps--Connecticut--New Milford--1897]. https://collections.library.yale.edu/catalog/11551283.