Randel, P. F. and Mendoza, N. (1983) “Effects of Concentrate Supplementation to Holstein Heifers Grazed at a High Stocking Rate on Intensively Managed Pastures from Breeding Age to Parturition”, The Journal of Agriculture of the University of Puerto Rico, 67(4), pp. 476–485. doi: 10.46429/jaupr.v67i4.7742.