Cardoso, Alcides, Reinaldo Oscar Potter, and Renato Antonio Dedecek. 1992. “Comparative Study of Soil Degradation in the Northwest of Paraná State”. Pesquisa Agropecuaria Brasileira 27 (2):349-53. https://doi.org/10.1590/S1678-3921.pab1992.v27.3656.