1. Integrable Hamiltonian Systems: Geometry, Topology, Classification;Bolsinov,2004
2. Global structure of continuous flows on 2-manifolds;Neumann;J. Differential Equations,1976
3. On the classification of flows on two-manifolds;Peixoto,1973
4. Classification of Morse–Smale flows on two-dimensional manifolds;Oshemkov;Sb. Math.,1998
5. Flows on 2-Dimensional Manifolds;Nikolaev,1999