Gibson, A. M.Oklahoma: A History of Five Centuries. University of Oklahoma Press, 1985. One of the best single volumes on history, economics, politics, and social conditions.
Morgan, H. Wayne, and Ann Hodges Morgan.Oklahoma: A History. Norton, 1984. Introductory overview.
Morris, John W., and E. C. McReynolds.Historical Atlas of Oklahoma. 3rd ed. University of Oklahoma Press, 1986. Good geographical source; first published in 1965.