Mohd Yusof, Abdul Halim, et al. “Fabrication and Effect of Sulfonated Poly (Ether Ether Ketone) With Cloisite15a® Nanoclays for Microbial Fuel Cell Application”. International Journal of Sustainable Construction Engineering and Technology, vol. 4, no. 1, Apr. 2013, pp. 63-74, https://publisher.uthm.edu.my/ojs/index.php/IJSCET/article/view/443.