1. C. Bonatti, V. Grines, Knots as topological invariant for gradient-like diffeomorphisms of the sphere S3, J. Dynamic. Contr. Syst., to appear
2. On decomposition of n-dimension manifolds to simple manifolds;Medvedev;Izv. Vyssh. Uchebn. Zaved. Mat.,1979
3. A unique decomposition theorem for 3-manifolds;Milnor;Amer. J. Math.,1962
4. Wild unstable manifolds;Pixton;Topology,1977
5. Differentiable dynamical systems;Smale;Bull. Amer. Math. Soc.,1967