Suresh Thokchom and  Partha Ghosh and  Somnath Ghosh,  Effect of Na2O Content on Durability of Geopolymer Mortars in Sulphuric Acid.   journal   = {International Journal of Civil and Environmental Engineering}, [online]. World Academy of Science, Engineering and Technology.
    March 2009, vol. 27(3). 193 - 198
    [viewed 14 November 2019]. Available from: https://publications.waset.org/pdf/7603.