Meiyue, Jiang, Some Existence Results on Periodic and Generalized Periodic Solutions for Singular Hamiltonian Systems, Acta Mathematica Sinica, New Series Chinese Journal of Mathematics, 9(2), 1993, pp. 129-138
In this paper, we use the variational method to study the existence of periodic and generalized periodic solutions of planar second order Hamiltonian systems when a singular potential is present. The results obtained are applied to the study of generalized periodic solutions of the Restricted Three-Body Problem and the Planar n-Body Problem.