1. Reynolds CMA. Use of vertical tillage and precision agriculture for energy optimization in primary soil tillage. Thesis, PhD. Engineering in production systems. Antonio Narro Autonomous Agrarian University. Saltillo, Coahuila, México 2014.
2. IDAE. Savings, energy efficiency and agricultural tillage systems. Institute for Diversification and Energy Saving. Madrid Spain. Corrected Second Edition 2006.
3. Adewoyin AO, Ajav EA. Fuel consumption of some tractor modelsforplowing operations in the sandy-loam soil of Nigeria at various speeds and plowing depth. Agric Eng Int: CIGR J. 2013; 15(3): 64-74.
4. FAO. "Manual of Integrated Soil Conservation Management Practices". 2003; (manual text). http://www.fao.org/ag/ags/agse/agse_s/7mo/iita.htm
5. Agamemnon R. Rotations and tillage in the southern semi-arid region of Buenos Aires. In Labranzas in the Semi-arid Region of Argentina. D. Buschiazzo, J. Panigatti and F. Babinec. Ed. INTA CERLAP- San Luis 1996.