Moreno, A., M. Moreno, F. Ribas, and M. Cabello. “Influence of Nitrogen Fertilizer on Grain Yield of Barley (Hordeum Vulgare L.) under Irrigated Conditions”. Spanish Journal of Agricultural Research, Vol. 1, no. 1, Mar. 2003, pp. 91-100, doi:10.5424/sjar/2003011-12.