Chow Khim, T., M. Ambar Yarmo, S. Radiman, and A. Ramli. “XPS Analysis of Dispersed Catalysts Prepared via w/O Microemulsion”. Malaysian Journal of Science, vol. 21, Dec. 2002, pp. 185-9, https://mjlis.um.edu.my/index.php/MJS/article/view/8886.