Pérez Escolar, Raúl, and M. A. Lugo López. “Influence of Degree of Clay-Mineral Crystallization and Free Iron Oxide Content on the Cation Exchange Capacity of Catalina and Cialitos Soils”. The Journal of Agriculture of the University of Puerto Rico, vol. 52, no. 2, Apr. 1968, pp. 148-54, doi:10.46429/jaupr.v52i2.11500.