1. DiTomaso, J.; Healy, E. Weeds of California and Other Western States, 1st ed. Agriculture and Natural Resources: University of California, CA, 2007; Vol. 1, 602–611.
2. Bryson, C.; DeFelice, M. Weeds of the Midwestern United States and Central Canada, 1st ed.; University of Georgia Press: Athens, GA, 2010; 183–188.