WASET
    S. U. Khan and  T. Ayub and  N. Shafiq,  Comparison of Physical and Chemical Properties of Micro-Silica and Locally Produced Metakaolin and Effect on the Properties of Concrete.   journal   = {International Journal of Civil and Environmental Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2017, vol. 128(8). 1085 - 1099
    [viewed 24 April 2024]. Available from: https://publications.waset.org/pdf/10007731.