MLA

Sanborn Map Company, issuing body. Insurance Maps of Bridgeport, Connecticut. Volume 1. 1913. https://collections.library.yale.edu/catalog/11037161.

APA, 6th edition

Sanborn Map Company, issuing body. (1913). Insurance maps of Bridgeport, Connecticut. Volume 1. [Annotations (Provenance), Atlases, Bridgeport, Cadastral maps, Connecticut, CtY-BR, Fire insurance maps, local, rbprov]. https://collections.library.yale.edu/catalog/11037161.