The Ability of Sludge from Wastewater Treatment Systems of Paper Plant to Improve Soil Fertility and Crop Growth. Global Journal of Science Frontier Research, [S. l.], v. 14, n. D10, p. 79–82, 2014. Disponível em: https://www.journalofscience.org/index.php/GJSFR/article/view/1357. Acesso em: 5 feb. 2026.