Hossein Kabir and  Mojtaba Sadeghi,  Unconfined Strength of Nano Reactive Silica Sand Powder Concrete.   journal   = {International Journal of Structural and Construction Engineering}, [online]. World Academy of Science, Engineering and Technology.
    March 2017, vol. 123(3). 369 - 373
    [viewed 20 October 2019]. Available from: https://publications.waset.org/pdf/10006817.