MLA

Division, United States. Adjutant-General's Office. Military Information. Military Map, Island of Puerto Rico, 1898 / Drawn by W. Morey Jr. C.E. Norris Peters Co., 0AD. https://collections.library.yale.edu/catalog/15832255.

APA, 6th edition

Division, U. S. A.-G. O. M. I. (0 C.E.). Military map, island of Puerto Rico, 1898 / drawn by W. Morey Jr. C.E. [Maps]. Norris Peters Co., https://collections.library.yale.edu/catalog/15832255.