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://twinhead.imath.kiev.ua/index.php/nosc/article/view/393. Acesso em: 21 jan. 2026.