| [1] | Arnold V I. Loss of stability of self-oscillations close to resonance and versal deformations of equivariant vector fields. Funct Anal Appl, 1977, 11(2): 85-92 | | [2] | Chen L, Wang M S. The relative position and number of limit cycles of a quadratic differential system. Acta Math Sinica (Chin Ser), 1979, 22(6): 751-758 | | [3] | Han M. Bifurcation Theory of Limit Cycles. Beijing: Science Press, 2013 | | [4] | Han M, Yang J, Tarta A, Yang G. Limit cycles near homoclinic and heteroclinic loops. J Dynam Differential Equations, 2008, 20: 923-944 | | [5] | Hilbert D. Mathematical problems. Transl Bull Amer Math Soc, 1902, 8: 437-479 | | [6] | Li W, Llibre J, Zhang X. Melnikov functions for period annulus, nondegenerate centers, heteroclinic and homoclinic cycles. Pacific J Math, 2004, 213(1): 49-77 | | [7] | Liu C, Xiao D. The smallest upper bound on the number of zeros of Abelian integrals. J Differential Equations, 2020, 269: 3816-3852 | | [8] | Shi S. A concrete example of the existence of four limit cycles for plane quadratic systems. Sci Sinica, 1980, 23: 153-158 | | [9] | Tian Y, Han M, Xu F. Bifurcations of small limit cycles in Liénard systems with cubic restoring terms. J Differential Equations, 2019, 267: 1561-1580 | | [10] | Xiong Y, Han M. New lower bounds for the Hilbert number of polynomial systems of Liénard type. J Differential Equations, 2014, 257: 2565-2590 | | [11] | Xiong Y, Hu J. Double homoclinic bifurcations by perturbing a class of cubic Z$_2$-equivariant polynomial systems with nilpotent singular points. Bull Sci Math, 2024, 190: 103377 |
|