Najamuddeen, G. ., M. B. Sayaya, A. L. Ala, and M. G. Garba. “Economics of Potatoes Production in Katsina Metropolis, Katsina State, Nigeria”. Scientific Journal of Crop Science, vol. 1, no. 3, Oct. 2012, pp. 48-54, http://sjournals.com/index.php/sjcs/article/view/1234.