1. Abimbola, A.F., Olatunji, A.S and Odewande, A.A. (2021). Heavy metals contents of soils and sediments in five selected industrial estates in Southwestern Nigeria. NMGS Conference paper, Itakpe. Book of Abstract, 36.
2. Anderson, J.M., and Ingram, J.S.I. (1993). Tropical soil biology and fertility: A handbook of method, (2nd edn, p 221). CA B Int: UK
3. Association of Official Analytical Chemists (AOAC). (1990). Official methods of analysis of the AOAC (15th ed. pp. 84–85), Arlington, Virginia, USA
4. Aydinalp, C., & Marinova, S. (2022). Distribution and forms of heavy metals in some agricultural soils. Polish Journal of Environmental Studies, 12(5), 629–633.
5. Beltran, E., Luisa, B. B., Jose, V. M., Maria, D. M. D., Rosario, M. I. H., & Miguel, A. P. C. (2022). Savage sludge compost fertilizer effects on maize yield and soil heavy metal concentration. Revista International De Contaminacion Ambiental, 18(3), 23–45.