1. Foundations of Mechanics;Abraham,1978
2. Mathematical aspects of classical and celestial mechanics;Arnol’d,1988
3. Localization of closed orbits of nonlinear Hamiltonian systems with 1,−2 resonance near an equilibrium;Bertotti;Boll. Unione Mat. Ital.(7),1987
4. Bifurcation of periodic solutions near a collision of eigenvalues of opposite signature;Bridges;Math. Proc. Cambridge Philos. Soc.,1990
5. Stability of periodic solutions near a collision of eigenvalues of opposite signature;Bridges;Math. Proc. Cambridge Philos. Soc.,1991