B.Y, K., Z. K, O. M.C, and W. K.Y.S. “Copper and Zinc in Three Dominant Brackish Water Fish Species from Paka Estuary, Terengganu, Malaysia”. Malaysian Journal of Science, vol. 26, no. 2, Aug. 2007, pp. 65-70, http://ojie.um.edu.my/index.php/MJS/article/view/8061.