“Influence of Inorganic Fertilizer (NPK 15:15:15) and Cacao (Theobroma cacao L) Leaf Litter Application Rates on Cowpea (Vigna unguiculata L.) Performance in the Tropics”, aijas, vol. 3, no. 1, pp. 14–32, Jun. 2020, doi: 10.46545/aijas.v3i1.15.