Caro-Costas, Rubén, Fernando Abruña, and José Vicente Chandler. “Effect of Three Levels of Fertilization on the Productivity of Stargrass Pastures Growing on a Steep Ultisol in the Humid Mountain Region of Puerto Rico”. The Journal of Agriculture of the University of Puerto Rico 60, no. 2 (April 1, 1976): 172–178. Accessed September 25, 2023.