Lugo-López, M.A. et al. 1957. Lack of Response of Some Food Crops to the Application of Synthetic Soil Conditioners to A Clay Soil in Lajas Valley. The Journal of Agriculture of the University of Puerto Rico. 41, 3 (Jul. 1957), 167–172. DOI:https://doi.org/10.46429/jaupr.v41i3.12615.