Trace element concentrations from Sao Francisco River - PR analyzed with PIXE technique - Rizzutto, Márcia de Almeida; Added, Nemitala; Tabacniks, Manfredo Harri; Espinoza-Quinones, F R; Palácio, S M; Galante, R M; Rossi, N.; Zenatti, D C; Rossi, F L; Welter, R A; Módenes, A N (Journal of Radionalytical and Nuclear Chemistry, 2006)