E. Oku, A. M. A. . dos Passos, S. S. . Quintino, N. C. . Odoh, and T. B. . Olowookere, “Soil fertility status of soils of Sudano-Sahelian and Humid Forest Zones of West Africa and some soil management strategies for smallholder farms”, EQA, vol. 46, pp. 25–36, Jan. 2021.