MLA

Sanborn-Perris Map Co., issuing body. Insurance Maps of Norwich, New London County, Connecticut. 1897. https://collections.library.yale.edu/catalog/11580662.

APA, 6th edition

Sanborn-Perris Map Co., issuing body. (1897). Insurance maps of Norwich, New London County, Connecticut. [Atlases--Connecticut--Norwich--1897, Cadastral maps--Connecticut--Norwich--1897, Fire insurance maps--Connecticut--Norwich--1897]. https://collections.library.yale.edu/catalog/11580662.