P. J. Udo, “Investigation of the Biochemical Composition of Heterobranchus longifilis, Clarias gariepinus and Chrysichthys nigrodigitatus of the Cross River, Nigeria”, Pak. J. Nutr., vol. 11, no. 10, pp. 963–966, Sep. 2012, doi: 10.3923/pjn.2012.963.966.