Koval’chuk PS, Kubenko VD. Application of the Averaging Method to the Investigation of Nonlinear Wave Processes in Elastic Systems with Circular Symmetry. Ukr. Mat. Zhurn. [Internet]. 2001Oct.25 [cited 2024Nov.24];53(10):1358-67. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/4355