Cherubin, M.R. et al. 2015. Sampling grid size for characterization of the spatial variability of phosphorus and potassium in an Oxisol. Pesquisa Agropecuaria Brasileira. 50, 2 (Feb. 2015), 168–177. DOI:https://doi.org/10.1590/S1678-3921.pab2015.v50.17888.