E.B, Saniman, Yahya M.Z.A, and Arof A.K. 2002. “X-Ray Photoelectron Spectroscopy for Probing Non-Bridging Oxygen in Silver Ion Conductors and Their Relationship to Ionic Conductivity”. Malaysian Journal of Science 21 (December):83-86. http://mojes.um.edu.my/index.php/MJS/article/view/8863.