MLA

Map, Sanborn, and issuing body Publishing Co. East Haddam, Conn. 1889. https://collections.library.yale.edu/catalog/11108017.

APA, 6th edition

Map, S., & Publishing Co., issuing body. (1889). East Haddam, Conn. [Cadastral maps--Connecticut--East Haddam (Town)--1889, Fire insurance maps--Connecticut--East Haddam (Town)--1889]. https://collections.library.yale.edu/catalog/11108017.