LLOYD N G, PEARSON J M.Conditions for a Centre and the Bifurcation of Limit Cycles in a Class of Cubic Systems [M]// Lecture Notes in Mathematics.Berlin:Springer, 1990:230-242.
LLOYD N G, PEARSON J M.A Cubic Kolmogorov System with Six Limit Cycles[J].Computers and Mathematics with Applications, 2002, 44(3-4):445-455. doi: 10.1016/S0898-1221(02)00161-X
LLIBRE J, VALLS C.Algebraic Invariant Curves and First Integrals for Riccati Polynomial Differential Systems[J].Proceedings of the American Mathematical Society, 2014, 142(10):3533-3543. doi: 10.1090/S0002-9939-2014-12085-5
LLIBRE J, VALLS C.Liouvillian First Integrals for Generalized Riccati Polynomial Differential Systems[J].Advanced Nonlinear Studies, 2015, 15(4):951-961.
ZHOU Z X, ROMANOVSKI V G, YU J.Centers and Limit Cycles of a Generalized Cubic Riccati System[J].International Journal of Bifurcation and Chaos, 2020, 30(2):2050021. doi: 10.1142/S0218127420500212
ROMANOVSKI V G, FERNANDES W, TANG Y L, et al.Linearizability and Critical Period Bifurcations of a Generalized Riccati System[J].Nonlinear Dynamics, 2017, 90(1):257-269. doi: 10.1007/s11071-017-3659-y
CHICONE C, JACOBS M.Bifurcation of Critical Periods for Plane Vector Fields[J].Transactions of the American Mathematical Society, 1989, 312(2):433-486. doi: 10.1090/S0002-9947-1989-0930075-2
林怡平, 李继彬.平面自治系统的规范型与闭轨族周期临界点[J].数学学报, 1991, 34(4):490-501.
ROUSSEAU C, TONI B.Local Bifurcations of Critical Periods in the Reduced Kukles System[J].Canadian Journal of Mathematics, 1997, 49(2):338-358. doi: 10.4153/CJM-1997-017-4
ZHANG W N, HOU X R, ZENG Z B.Weak Centers and Bifurcation of Critical Periods in Reversible Cubic Systems[J].Computers & Mathematics With Applications, 2000, 40(6-7):771-782.
刘一戎, 陈海波.奇点量公式的机器推导与一类三次系统的前10个鞍点量[J].应用数学学报, 2002, 25(2):295-302.
HUANG W, LIU Y.Bifurcations of Limit Cycles from Infinity for a Class of Quintic Polynomial System[J].Bulletin Des Sciences Mathématiques, 2004, 128(4):291-302. doi: 10.1016/j.bulsci.2004.02.002
LIU Y R, HUANG W T.A New Method to Determine Isochronous Center Conditions for Polynomial Differential Systems[J].Bulletin Des Sciences Mathématiques, 2003, 127(2):133-148. doi: 10.1016/S0007-4497(02)00006-4
CHEN T, HUANG W T, REN D C.Weak Centers and Local Critical Periods for a Z2-Equivariant Cubic System[J].Nonlinear Dynamics, 2014, 78(4):2319-2329. doi: 10.1007/s11071-014-1560-5