Cite

(MONTANA) Roberts, E. J. Montana Extension. The Saint Paul, Minneapolis and Manitoba Ry. Co. Scale 12 miles to 1 inch.

MLA

E.J, Roberts. (MONTANA) Roberts, E. J. Montana Extension. The Saint Paul, Minneapolis and Manitoba Ry. Co. Scale 12 Miles to 1 Inch. 1887. https://collections.library.yale.edu/catalog/2016956.

APA, 6th edition

E.J, R. (1887). (MONTANA) Roberts, E. J. Montana Extension. The Saint Paul, Minneapolis and Manitoba Ry. Co. Scale 12 miles to 1 inch. [Maps]. https://collections.library.yale.edu/catalog/2016956.