Vélez-Santiago, J., and J. A. Arroyo-Aguilú. “Effect of Three Harvest Intervals on Yield and Nutritive Value of Seven Napiergrass Cultivars”. The Journal of Agriculture of the University of Puerto Rico, vol. 65, no. 2, Apr. 1981, pp. 129-37, doi:10.46429/jaupr.v65i2.7584.