Sotomayor-Ríos, Antonio, et al. “Response of Forage Sorghums Millo Blanco and Greenleaf Sudangrass and Their Hybrids to Planting Dates”. The Journal of Agriculture of the University of Puerto Rico, vol. 82, no. 3-4, Oct. 1998, pp. 151-62, doi:10.46429/jaupr.v82i3-4.4073.