Карнаухов, Василь Григорович, et al. “STRUCTURE OF AMPLITUDE CONSTITUTIVE EQUATIONS FOR NON-ELASTIC PIEZOELECTRIC SOLIDS UNDER HARMONIC LOADING”. PRECARPATHIAN BULLETIN OF THE SHEVCHENKO SCIENTIFIC SOCIETY. Number, no. 1(21), Mar. 2019, pp. 69-77, https://pvntsh.nung.edu.ua/index.php/number/article/view/182.