Prado, R. de M., Roque, C. G., & de Souza, Z. M. (2002). Resistance to penetration and density of a soil submitted to different systems of tillage and cultivations. Pesquisa Agropecuaria Brasileira, 37(12), 1795–1801. https://doi.org/10.1590/S1678-3921.pab2002.v37.6533