1. On the infinitesimal geometry of integrable systems;Baider,1996
2. The Pendulum. A Case Study in Physics;Baker,2005
3. A variational criterion for non-integrability;Bolotin;Boll Russian J Math Phys,1997
4. A variational construction of chaotic trajectories for a Hamiltonian system on a torus;Bolotin;Boll Unione Mat Ital Sez B Artic Ric Mat,1998
5. Differential Galois theory;Beukers,1992