Beaver, James S., and Obed Román-Hernández. “Green-Shell Bean Production in Puerto Rico at Different Planting Dates”. The Journal of Agriculture of the University of Puerto Rico 78, no. 3-4 (October 1, 1994): 131–136. Accessed May 24, 2022. https://revistas.upr.edu/index.php/jaupr/article/view/4281.