1. Geometrical Methods in the Theory of Ordinary Differential Equations;Arnold,1983
2. Versal deformations of singularity of a vector field on the plane in the case of zero eigenvalues;Bogdanov;Proc. Petrovki Sem.,1976
3. Applications of Center Manifold Theory;Carr,1981
4. Abelian integrals and bifurcation theory;Carr;J. Differential Equations,1985
5. Uniqueness of periodic orbits in some vector fields with codimension two singularities;Chow;J. Differential Equations,1989