Meyer, Roy W.: The Village Indians of the Upper Missouri. The Mandans, Hidatsas, and Arikaras. Lincoln and London, 1977, map facing p. 112. Or see American Memory. (http://memory.loc.gov). Indian Land Cession in the United States, 1784 to 1894. Serial 4015, 56th Congress, 1st Session, pp. 852–853. Map: Dakota 1.