del Valle, Reinaldo, Carlos E. Ortiz, and Miguel A. Santiago-Córdova. “FERTILIZATION OF ARRACACHA IN AN ULTISOL”. The Journal of Agriculture of the University of Puerto Rico 79, no. 3-4 (October 1, 1995): 183–185. Accessed April 18, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/4314.