Udo, Paul J. “Investigation of the Biochemical Composition of Heterobranchus Longifilis, Clarias Gariepinus and Chrysichthys Nigrodigitatus of the Cross River, Nigeria”. Pakistan Journal of Nutrition, vol. 11, no. 10, Sept. 2012, pp. 963–966, https://doi.org/10.3923/pjn.2012.963.966.