MLA

Map, Sanborn, and issuing body Publishing Co. Groton, Conn. 1884. https://collections.library.yale.edu/catalog/11123209.

APA, 6th edition

Map, S., & Publishing Co., issuing body. (1884). Groton, Conn. [Cadastral maps--Connecticut--Groton--1884, Fire insurance maps--Connecticut--Groton--1884]. https://collections.library.yale.edu/catalog/11123209.