Umeghalu, I. ., E. . Nwuba, D. . Onukwuli, I. . Okonkwo, and J. . Ngini. “Kinetics of Biogas Production from Fermentation Broth of Wild Cocoyam Codigested With Cow Paunch in Batch Mode”. Scientific Journal of Pure and Applied Sciences, vol. 4, no. 3, Mar. 2015, pp. 98-104, http://www.sjournals.com/index.php/sjpas/article/view/463.