Lugo-López, M. A., E. Hernández-Medina, and P. Landrau, Jr. “Differential Response of Some Tropical Soils to Additions of Organic Matter”. The Journal of Agriculture of the University of Puerto Rico 40, no. 1 (January 1, 1956): 70–77. Accessed November 20, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/12663.