MLA

Sanborn Map Company, issuing body. Insurance Maps of Putnam, Windham County, Connecticut. 1910. https://collections.library.yale.edu/catalog/11594409.

APA, 6th edition

Sanborn Map Company, issuing body. (1910). Insurance maps of Putnam, Windham County, Connecticut. [Atlases--Connecticut--Putnam--1910, Cadastral maps--Connecticut--Putnam--1910, Fire insurance maps--Connecticut--Putnam--1910]. https://collections.library.yale.edu/catalog/11594409.