Campos, R.A., Machado, W. and Stipp, N.A.F. 2005. Diagnosis of an enviromental system: the case hydrographical micro basin of Ribeirão das Marrecas in Londrina - PR - Brazil. Sociedade & Natureza. 1, 1 (May 2005). DOI:https://doi.org/10.14393/SN-v1-2005-9716.