Rodrigues, José Guilherme Lança, et al. “Physical Characterization of Soil and Operational Performance of Agricultural Machines in the Deployment of Forage Sorghum”. Semina: Ciências Agrárias, vol. 32, no. 4Sup1, Dec. 2011, pp. 1813-24, doi:10.5433/1679-0359.2011v32n4Sup1p1813.