Martínez, G. A., Peña-Córdova, L. and Figueroa, L. A. (1996) “A thermodynamic evaluation of the addition of calcium and magnesium to an Ultisol: II CaS04 addition”, The Journal of Agriculture of the University of Puerto Rico, 80(1-2), pp. 1–12. doi: 10.46429/jaupr.v80i1-2.4318.