Chioderoli, Carlos Alessandro, et al. “PERFORMANCE OF A GRAIN DRILL IN FUNCTION OF SOIL TILLAGE AND MAIZE CROP SPACING”. Pesquisa Agropecuária Tropical [Agricultural Research in the Tropics], vol. 40, no. 4, Dec. 2010, pp. 462-7, https://doi.org/10.5216/pat.v40i4.7647.