1. Loss of stability of self-oscillation close to resonance and versal deformations of equivalent vector fields;Arnold;Funct. Anal. Appl.,1977
2. On the number and distributions of limit cycles in a cubic system;Han;China Ann. Math.,2002
3. High order bifurcations of limit cycles;Iliev;J. Differential Equations,1999
4. Hilbert's 16th problem and bifurcations of planar polynomial vector fields;Li;International J. Bifurcation Chaos,2003
5. Polynomial systems: a lower bound for the weakened 16th Hilbert problem;Li;Extracte Math.,2001