Hanyotee, Saifon, and Metta Chareonpenich. 2013. “Synthesis of High Purity ZSM-5 Zeolite from Lignite Fly Ash via Two-stage Process”. Engineering and Applied Science Research 31 (4):409-24. https://ph01.tci-thaijo.org/index.php/easr/article/view/6774.