Olatunji Ayotunde, E., B. Obeten Offem, and F. Bekeh Ada. “Heavy Metal Profile of Water, Sediment and Freshwater Cat Fish, Chrysichthys Nigrodigitatus (Siluriformes: Bagridae), of Cross River, Nigeria”. 2012. Revista De Biología Tropical, vol. 60, no. 3, Sept. 2012, pp. 1289-01, doi:10.15517/rbt.v60i3.1807.