E. J. DANICKI, “An approximation to the planar harmonic impedance for interface waves in piezoelectric body”, Arch. Acoust., vol. 34, no. 2, pp. 189–196, Jan. 2009, Accessed: Apr. 29, 2025. [Online]. Available: https://acoustics3.ippt.pan.pl/index.php/aa/article/view/575