Ukom, A., Ojimelukwe, P., & Okpara, D. (2009). Nutrient Composition of Selected Sweet Potato [Ipomea batatas (L) Lam] Varieties as Influenced by Different Levels of Nitrogen Fertilizer Application. Pakistan Journal of Nutrition, 8(11), 1791–1795. https://doi.org/10.3923/pjn.2009.1791.1795