“Heavy Metal Content of Agricultural Soils in a Tropical Sudan Savannah Area: Katsina State, North-Western Nigeria”, GJHSS, vol. 19, no. B1, pp. 43–50, Jan. 2019, Accessed: Feb. 19, 2026. [Online]. Available: https://socialscienceresearch.org/index.php/GJHSS/article/view/2837