Cite

City of Baltimore topographical survey : Sheet 1N. - 4W. / made under the direction of H.T. Douglas, chief engineer.

MLA

City of Baltimore Topographical Survey : Sheet 1N. - 4W. / Made under the Direction of H.T. Douglas, Chief Engineer. Photo-Lith. by A. Hoen, 1894. https://collections.library.yale.edu/catalog/15811182.

APA, 6th edition

City of Baltimore topographical survey : Sheet 1N. - 4W. / made under the direction of H.T. Douglas, chief engineer. (1894). [Maps]. Photo-Lith. by A. Hoen, https://collections.library.yale.edu/catalog/15811182.