Mahsa Shafaei Bajestani and  Mahmoud Yazdani and  Aliakbar Golshani,  Experimental Determination of Shear Strength Properties of Lightweight Expanded Clay Aggregates Using Direct Shear and Triaxial Tests.   journal   = {International Journal of Geotechnical and Geological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2018, vol. 134(2). 107 - 113
    [viewed 13 August 2020]. Available from: https://publications.waset.org/pdf/10008592.