H. P. dos Santos, E. M. Reis, and L. H. Andia, “Crop rotation in Guarapuava. XV. Economic analysis of four rotation systems for wheat under no-tillage”, PAB, vol. 31, no. 8, pp. 569–574, Aug. 1996, doi: 10.1590/S1678-3921.pab1996.v31.4521.