Tourino, Maria Cristina Cavalheiro, et al. “Row Spacing, Plant Density and Intrarow Plant Spacing Uniformity Effect on Soybean Yield and Agronomic Characteristics”. Pesquisa Agropecuaria Brasileira, vol. 37, no. 8, Aug. 2002, pp. 1071-7, doi:10.1590/S1678-3921.pab2002.v37.6440.