Romero, I., A. Benito, N. Dominguez, E. Garcia-Escudero, and I. Martin. “Leaf Blade and Petiole Nutritional Diagnosis for Vitis Vinifera L. Cv. Tempranillo by Deviation from Optimum Percentage Method”. Spanish Journal of Agricultural Research, Vol. 12, no. 1, Jan. 2014, pp. 206-14, doi:10.5424/sjar/2014121-4308.