Quiñones, A., B. Martínez-Alcántara, U. Chi-Bacab, and F. Legaz. “Improvement of N Fertilization by Using the Nitrification Inhibitor DMPP [3,4-Dimethylpirazole Phosphate] in Drip-Irrigated Citrus Trees”. Spanish Journal of Agricultural Research, Vol. 7, no. 1, Mar. 2009, pp. 190-9, doi:10.5424/sjar/2009071-411.