Barrientos Perez, Facundo, Fernando Borrego-Escalante, and Peter Felker. “Collaborative Mexico/United States Initiative to Breed Freeze Tolerant Fruit and Forage Opuntia Varieties”. Journal of the Professional Association for Cactus Development (July 25, 1992): 49–55. Accessed December 19, 2025. https://www.jpacd.org/jpacd/article/view/450.