WASET
    Sam S. Hashemi,  A Failure Criterion for Unsupported Boreholes in Poorly Cemented Granular Formations.   journal   = {International Journal of Civil and Environmental Engineering}, [online]. World Academy of Science, Engineering and Technology.
    September 2016, vol. 119(11). 1393 - 1400
    [viewed 25 April 2024]. Available from: https://publications.waset.org/pdf/10005705.