MLA

Map, Sanborn, and issuing body Publishing Co. Darien, Conn. 1887. https://collections.library.yale.edu/catalog/11098240.

APA, 6th edition

Map, S., & Publishing Co., issuing body. (1887). Darien, Conn. [Cadastral maps--Connecticut--Darien--1887, Fire insurance maps--Connecticut--Darien--1887]. https://collections.library.yale.edu/catalog/11098240.