OKALEBO, J. Inorganic resources management for sustainable soil productivity. East African Agricultural and Forestry Journal, [S. l.], v. 69, n. 2, p. 119–129, 2005. DOI: 10.4314/eaafj.v69i2.1813. Disponível em: https://www.ajol.info/index.php/eaafj/article/view/1813. Acesso em: 10 sep. 2026.