A nonlinear Noether boundary-value problem for a parametric excitation system. Neliniini Kolyvannya, [S. l.], v. 17, n. 1, p. 137–148, 2014. Disponível em: https://nosc.imath.kiev.ua/index.php/nosc/article/view/734. Acesso em: 12 apr. 2026.