MLA

Sanborn Map Company, issuing body. Insurance Maps of South Norwalk, Including East Norwalk, Rowayton, Bell Island, and Roton Point, Fairfield Co., Connecticut. 1912. https://collections.library.yale.edu/catalog/11623294.

APA, 6th edition

Sanborn Map Company, issuing body. (1912). Insurance maps of South Norwalk, including East Norwalk, Rowayton, Bell Island, and Roton Point, Fairfield Co., Connecticut. [Atlases--Connecticut--Norwalk--1912, Atlases--Connecticut--Norwalk--South Norwalk--1912, Cadastral maps--Connecticut--Norwalk--1912, Cadastral maps--Connecticut--Norwalk--South Norwalk--1912, Fire insurance maps--Connecticut--Norwalk--1912, Fire insurance maps--Connecticut--Norwalk--South Norwalk--1912]. https://collections.library.yale.edu/catalog/11623294.