Vicente-Chandler, José, Rubén Caro-Costas, and Elvin G. Boneta. 1966. “High Crop Yields Produced With or Without Tillage on 3 Typical Soils of the Humid Mountain Region of Puerto Rico”. The Journal of Agriculture of the University of Puerto Rico 50 (2):146-50. https://doi.org/10.46429/jaupr.v50i2.3721.