MLA

Company, Northern Pacific Railway. (MONTANA) [Anon.] [Untitled Map of a Part of North Central Montana.] Ink on Oil Cloth, 26-1/2 x 36 1/2. (Map 36). 0AD. https://collections.library.yale.edu/catalog/2016958.

APA, 6th edition

Company, N. P. R. (0 C.E.). (MONTANA) [Anon.] [Untitled map of a part of north central Montana.] Ink on oil cloth, 26-1/2 x 36 1/2. (Map 36). https://collections.library.yale.edu/catalog/2016958.