Hayder H. Kareem and  Shunqi Pan,  Impact of Interface Soil Layer on Groundwater Aquifer Behaviour.   journal   = {International Journal of Geotechnical and Geological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2018, vol. 134(2). 87 - 95
    [viewed 20 January 2020]. Available from: https://publications.waset.org/pdf/10008558.