de Carvalho, J. R. P.; da Silveira, P. M.; Vieira, S. R. Geostatistics to Determine Spatial Variability of Soil Chemical Properties Using Different Preparation Systems. PAB 2002, 37 (8), 1151-1159. https://doi.org/10.1590/S1678-3921.pab2002.v37.6449.