MLA

Eldridge, George, 1821-1879. Eldridge's new chart of Boston Harbor : compiled from the latest surveys / engraved by G.W. Boynton.. BRBL_00461. 1891. https://collections.library.yale.edu/catalog/15654663.

APA, 6th edition

Eldridge, George, 1821-1879. (["BRBL_00461"])(1891)[Eldridge's new chart of Boston Harbor : compiled from the latest surveys / engraved by G.W. Boynton.]. https://collections.library.yale.edu/catalog/15654663.