ADACHI, S. Non-collision periodic solutions of prescribed energy problem for a class of singular Hamiltonian systems. Topological Methods in Nonlinear Analysis, [S. l.], v. 25, n. 2, p. 275–296, 2005. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2005.014. Acesso em: 22 lip. 2024.