Michael Udoidiong, Okon, Blessing Julius Oribhabor, Etim Effiong Munam, and Janet James Bernard. “Assessment of the Impact of Human Settlement on the Heavy Metal Concentrations of Lower Cross River, Nigeria”. Pure and Applied Science Advances 2, no. 7 (July 31, 2013): 270-278. Accessed January 12, 2026. http://www.sjournals.com/index.php/sjpas/article/view/970.