Akinrinde, E., Onanuga, O., Bello, O., & Obigbesan, G. (2004). Efficiency of indigenous ground phosphate rocks, organic fertilizer and their mixtures for maize performance in two Nigerian alfisols. Moor Journal of Agricultural Research, 4(1), 1–7. https://doi.org/10.4314/mjar.v4i1.31745