MLA

Sanborn Map Company, issuing body. Portland, Including Gildersleeve, Middlesex County, Connecticut. 1924. https://collections.library.yale.edu/catalog/11593820.

APA, 6th edition

Sanborn Map Company, issuing body. (1924). Portland, including Gildersleeve, Middlesex County, Connecticut. [Atlases--Connecticut--Portland--1924, Cadastral maps--Connecticut--Portland--1924, Fire insurance maps--Connecticut--Portland--1924]. https://collections.library.yale.edu/catalog/11593820.