MLA

Sanborn-Perris Map Co., issuing body. Newtown, Fairfield Co., Conn't. 1889. https://collections.library.yale.edu/catalog/11580133.

APA, 6th edition

Sanborn-Perris Map Co., issuing body. (1889). Newtown, Fairfield Co., Conn't. [Atlases--Connecticut--Newtown--1889, Cadastral maps--Connecticut--Newtown--1889, Fire insurance maps--Connecticut--Newtown--1889]. https://collections.library.yale.edu/catalog/11580133.