PRYKARPATSKY, Ya. A.; SAMOILENKO, A. M. Investigation of invariant deformations of integral manifolds of adiabatically perturbed completely integrable hamiltonian systems. I. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 51, n. 10, p. 1379–1390, 1999. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4737. Acesso em: 5 dec. 2025.