Lugo López, M. A., and J. A. Bonnet. “Utilization of Organic Soils in Puerto Rico”. The Journal of Agriculture of the University of Puerto Rico 35, no. 2 (April 1, 1951): 57–65. Accessed April 19, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/12821.