Vicente-Chandler, José, Fernando Abruña, and Servando Silva. “Effect of Shade Trees on Yields of Five Crops in the Humid Mountain Region of Puerto Rico”. The Journal of Agriculture of the University of Puerto Rico 50, no. 3 (July 1, 1966): 218–225. Accessed November 22, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/3459.