Rates, patterns and proximate causes. Ecological implications of livestock herbivory in the west. Bohrer, V. L. 1975. The prehistoric and historic role of the cool-season grasses in the Southwest . Branson, F. A. 1985.
Vegetation changes on western rangelands.
Range Monograph No. 2. Society for Range Management, Denver, CO. Cottam, W. P. and Stewart, G. 1940. Plant succession as a result of grazing and meadow desiccation by erosion since settlement in 1862 . Hall, D. O. and Scurlock, J. M. O. 1991. Climate change and productivity of natural grasslands .