M. J. Ochoa, L. M. González-Flores, J. M. Cruz-Rubio, L. Portillo, and J. F. Gómez-Leyva, “Effect of substrate and gibberellic acid (GA3) on seed germination in ten cultivars of Opuntia sps”., J PROF ASSOC CACTUS, vol. 17, pp. 50–60, May 2015.