Abruña, F. et al. 1983. Crop Response to Soil Acidity Factors in Ultisols and Oxisols in Puerto Rico. VIII. Yams. The Journal of Agriculture of the University of Puerto Rico. 67, 4 (Oct. 1983), 438–445. DOI:https://doi.org/10.46429/jaupr.v67i4.7738.