A. Chattopadhyay and A. Chakraborty, “Sh Waves in a Porous Layer of Nonuniform Thickness”, Eng. Trans., vol. 34, no. 1-2, pp. 3–13, Jun. 1986, Accessed: Jan. 17, 2026. [Online]. Available: http://et.ippt.gov.pl/index.php/et/article/view/1793