(1)
Tiznado-Hernández, M. E.; Fortiz-Hernández, J.; Ojeda-Contreras, Ángel J.; Rodríguez-Félix, A. Use of the Elliptical Mathematical Formula to Estimate the Surface Area of Cladodes in Four Varieties of Opuntia Ficus-Indica. J PROF ASSOC CACTUS 2010, 12, 98-109.