[1] N. E. I and O. U. B., “Effect of Different Levels of N.P.K. 15:15:15 Fertilizer Application on the Yield of Sweet Potato (Ipomea Batatas) in South-South Nigeria,” IJEAB, vol. 2, no. 5, pp. 2336–2339, 2017, doi: 10.22161/ijeab/2.5.8.