1. Vines, R. A., Trees, Shrubs, and Woody Vines of the Southwest. University of Texas Press, Austin, TX, 1984.
2. Adams, H. R. and Camp, B. J., Toxicon, 1966, 4, 85.
3. Broughton, I. B. and Hardy, W. T., 54th Ann. Rep., Texas Agric. Exper. Stat., 1941, p. 159.