MLA

Sanborn Map Company, issuing body. Insurance Maps of Winsted, Litchfield County, Connecticut. 1909. https://collections.library.yale.edu/catalog/11681838.

APA, 6th edition

Sanborn Map Company, issuing body. (1909). Insurance maps of Winsted, Litchfield County, Connecticut. [Atlases--Connecticut--Winsted--1909, Cadastral maps--Connecticut--Winsted--1909, Fire insurance maps--Connecticut--Winsted--1909]. https://collections.library.yale.edu/catalog/11681838.