Rocha, Marcelo Monteiro da, Jorge Kazuo Yamamoto, and Helano Regis da Nóbrega Fonteles. 2009. “ Ordinary Co-Kriging Versus Kriging With External Drift Correction: Applications to the Evaluation of the Potentiometric Level of a Free Aquifer ”. Geologia USP. Série Científica 9 (1): 73-84. https://doi.org/10.5327/Z1519-874X2009000100005.