H. Alyosef, H. Uhlig, T. Muenster, G. Kloess, W. Einicke, R. Glaeser, D. Enke, Biogenic Silica from Rice Husk Ash - Sustainable Sources for the Synthesis of Value Added Silica, Chemical Engineering Transactions. 37 (2014) 667-672. doi:10.3303/CET1437112.