dos Santos, H. P., & Reis, E. M. (1994). Crop rotation in Guarapuava. XVII. Energetic efficiency of rotation systems for barley crop, under no-tillage. Pesquisa Agropecuaria Brasileira, 29(7), 1075–1081. https://doi.org/10.1590/S1678-3921.pab1994.v29.4150