Radzali, R., N. H. Osman, Y. W. Fen, and J. L. Ying Chyi. “Electrical Characterization of Chitosan Film for Mercury Ion Detection by Using Four-Point Probe Method”. Asian Journal of Applied Sciences, vol. 4, no. 5, Oct. 2016, https://www.ajouronline.com/index.php/AJAS/article/view/4004.