"Guayule"(PDF). The University of Arizona College of Agriculture & Life Sciences. Archived from the original(PDF) on June 8, 2019. Retrieved April 29, 2020.
Bowers, Janice Emily (1990). Natural rubber-producing plants for the United States. U.S. Dept. of Agriculture, National Agricultural Library. p. 20. hdl:2027/uiug.30112020072465.
"Guayule"(PDF). The University of Arizona College of Agriculture & Life Sciences. Archived from the original(PDF) on June 8, 2019. Retrieved April 29, 2020.