Bifurcation of coisotropic invariant tori under locally Hamiltonian perturbations of integrable systems and nondegenerate deformations of the symplectic structure. Neliniini Kolyvannya, [S. l.], v. 9, n. 2, p. 221–232, 2006. Disponível em: https://nosc.imath.kiev.ua/index.php/nosc/article/view/393. Acesso em: 12 apr. 2026.