1. Perturbations and Hopf bifurcation of the planar discontinuous dynamical system;Akhmet;Nonlinear Anal.,2005
2. Theory of Bifurcations of Dynamic Systems on a Plane;Andronov,1973
3. Loss of stability of self-oscillations close to resonance and versal deformations of equivariant vector fields;Arnold;Funct. Anal. Appl.,1977
4. Geometric Methods in Theory of Ordinary Differential Equations;Arnold,1983
5. On the number of limit cycles which appear with the variation of coefficients from an equilibrium position of focus or center type;Bautin;Mat. Sb. (N.S.),1952