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