Okole, P. A., Ojobor, S. A., and Akparobi, S. O., “USE OF FORMULATED FERTILIZERS FOR SOIL CHEMICAL PROPERTIES IMPROVEMENT AND OKRA (Abelmoschus esculentus L. Moench) YIELD IN IBUSA, DELTA STATE”, njaat, vol. 5, no. 3B, pp. 159–168, Oct. 2025.