Estevam-Alves, Régia, et al. “THE DEGRADATION AND FRAGILITY OF SOILS IN SOUTHWESTERN GOIAS: THE WATERSHED CASE OF RIBEIRAO DA PICADA”. Revista Geográfica De América Central., vol. 1, no. 56, May 2016, pp. 235-58, https://doi.org/10.15359/rgac.1-56.10.