1. The Vegetation of Oklahoma
2. 2E.R. Cook, D.M. Meko, D.W. Stahle, and M.K. Cleaveland, 1996, Tree-Ring reconstructions of past drought across the coterminus United States: tests of a regression method and calibration/verification resultsTree rings environment and humanity (ed. by J.S. Dean, D.M. Meko and T.W. Swetnam), pp. 155169 Radiocarbon, Tucson, Arizona.
3. 3L.G. Duck, and J.B. Fletcher, 1945A survey of the game and fur bearing animals of Oklahoma. Oklahoma Game and Fish Commission Bulletin No. 3 144
4. The Vegetation of the Western Cross Timbers
5. 5J.M. Goodman, 1977, Physical Environments of OklahomaGeography of Oklahoma The Oklahoma Series. Vol. 6. (ed. by J.W. Morris), pp. 924 Oklahoma Historical Society, Oklahoma City, Oklahoma.