M.Z.A, M., K. Zarina K.A, N. Adilah, and I. A. “Effects of Yâ‚‚O₃, Pd and Rhâ‚‚O₃ Added in TiOâ‚‚ Based Sensors Materials”. Malaysian Journal of Science, vol. 21, Dec. 2002, pp. 113-6, https://samudera.um.edu.my/index.php/MJS/article/view/8868.