Murillo, J.M., F. Moreno, E. Madejón, I.F. Girón, and F. Pelegrín. 2006. “Improving Soil Surface Properties: A Driving Force for Conservation Tillage under Semi-Arid Conditions”. Spanish Journal of Agricultural Research 4 (1), 97-104. https://doi.org/10.5424/sjar/2006041-180.