MLA

Sanborn Map Company, issuing body. Old Saybrook, Middlesex County, Connecticut. 1923. https://collections.library.yale.edu/catalog/11580677.

APA, 6th edition

Sanborn Map Company, issuing body. (1923). Old Saybrook, Middlesex County, Connecticut. [Atlases--Connecticut--Old Saybrook--1923, Cadastral maps--Connecticut--Old Saybrook--1923, Fire insurance maps--Connecticut--Old Saybrook--1923]. https://collections.library.yale.edu/catalog/11580677.