The use of tomography to evaluate soil compaction in a red yellow podzolic area of the Brazilian Northeast - Macedo, A.; Vaz, M P; Naime, J M; Cruvinel, P E; Bassoi, L H; Bacchi, Osny Oliveira Santos; Fante Junior, L; Oliveira, J. C. M. de (Advances in agricultural tomography, 2000)