Kalaw, M. E. L.; Culaba, A. B.; Nguyen, H. T.; Nguyen, K.; Hinode, H.; Kurniawan, W.; Gallardo, S. M.; Promentilla, M. A. B. Mechanical and Thermal Properties of Geopolymers from Mixtures of Coal Ash and Rice Hull Ash Using Water Glass Solution As Activator. ASEAN J. Chem. Eng. 2015, 15, 51-61.