P. Ogbuewu, I., V. U. Odoemenam, A. A. Omede, C. S. Durunna, O. O. Emenalom, M. C. Uchegbu, I. C. Okoli, and M. U. Iloeje. “Livestock Waste and Its Impact on the Environment”. Scientific Journal of Review, vol. 1, no. 2, Aug. 2012, pp. 17-32, http://sjournals.com/index.php/sjr/article/view/684.