1. Gould F. W.1962.Texas plants—a checklist and ecological summary.Texas Agr. Exp. Sta. A. and M. College College Station.
2. Hafsten U.1961.Pleistocene development of vegetation and climate in the southern high plains as evidenced by pollen analysis p.59–91.InF. Wendorf [compiler] Paleoecology of the Llano Estacado. Mus. New Mexico Press (Publ. no. 1 Ft. Burgwin Res. Center).
3. Plants of Arches National Monument;Harrison B. F.;Brigham Young Univ., Sci. Bull., Biol. Ser.,1964
4. Arizona Flora