WASET
    JanuszKwaƛniewski and  IreneuszDominik and  KrzysztofLalik,  Rock Thickness Measurement by Using Self-Excited Acoustical System.   journal   = {International Journal of Geotechnical and Geological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2014, vol. 86(2). 401 - 405
    [viewed 28 March 2024]. Available from: https://publications.waset.org/pdf/9997554.