MLA

Map, Sanborn, and issuing body Publishing Co. Guilford, New Haven Co., Conn. 1889. https://collections.library.yale.edu/catalog/11129041.

APA, 6th edition

Map, S., & Publishing Co., issuing body. (1889). Guilford, New Haven Co., Conn. [Atlases--Connecticut--Guilford--1889.--local, Cadastral maps--Connecticut--Guilford--1889.--local]. https://collections.library.yale.edu/catalog/11129041.