Mahmoud Hassanlourad and  Mehran Naghizadehrokni and  Vahid Molaei,  A Numerical Study of Seismic Response of Shallow Square Tunnels in Two-Layered Ground .   journal   = {International Journal of Geological and Environmental Engineering}, [online]. World Academy of Science, Engineering and Technology.
    February 2019, vol. 147(3). 167 - 174
    [viewed 12 December 2019]. Available from: https://publications.waset.org/pdf/10010156.