Sofonea, M., and EL‐H. Essoufi. “A Piezoelectric Contact Problem With Slip Dependent Coefficient of Friction”. Mathematical Modelling and Analysis 9, no. 3 (September 30, 2004): 229-242. Accessed February 6, 2025. https://transport.vgtu.lt/index.php/MMA/article/view/9732.