M. A. Simonete, J. de C. Kiehl, C. A. Andrade, and C. F. A. Teixeira, “Effect of sewage sludge in a Ultisol and on growth and nutrition of maize”, PAB, vol. 38, no. 10, pp. 1187–1195, Oct. 2003, doi: 10.1590/S1678-3921.pab2003.v38.6689.