Bonnet, J. A., M. A. Lugo-López, and M. Rico-Ballester. “Effect of Incorporating Organic Materials into A Clay Soil of Lajas Valley on the Yields of Food Crops”. The Journal of Agriculture of the University of Puerto Rico 41, no. 3 (July 1, 1957): 173–178. Accessed March 28, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/12616.