Carvalho, José Ruy Porto de, et al. “Geostatistical Interpolation in the Analysis of Spatial Distribution of Annual Rainfall and of Its Relationship to Altitude”. Pesquisa Agropecuaria Brasileira, vol. 47, no. 9, Nov. 2012, pp. 1235-42, doi:10.1590/S1678-3921.pab2012.v47.10819.