Map of the County of Gloucester ... by C. & J. Greenwood. Engraved by J. & C. Walker.
MLA
Map of the County of Gloucester ... by C. & J. Greenwood. Engraved by J. & C. Walker. Greenwood & Co., 0AD. https://collections.library.yale.edu/catalog/15350018.
APA, 6th edition
Map of the County of Gloucester ... by C. & J. Greenwood. Engraved by J. & C. Walker. (0 C.E.). [Maps]. Greenwood & Co., https://collections.library.yale.edu/catalog/15350018.