[1] HAN Mao-an. On periodic, unbounded and oscillating solutions of system x = φ(y)-F(x),y =-g(x) [J]. J Nanjing University Math Biquarterly, 1984,1(1):89-101. [2] HAN Mao-an. On boundedness of solutions and existence of limit cycles of Lienard systems[J].Disc Cont Dynamical System, 2001,7 (5): 426-434. [3] Hara T. Notice on the Vinogrard type theorem for Lienard systems[J]. Nonlinear Analysis, TMA,1994,22(12): 1437-1443. [4] Hara T, Sugie J. When all trajectories in the Lienard plane cross the vertical isocline[J]. NoDEA,1995,6(2):527-551. [5] Hara T, Yoneyama T, Sugie J. A necessary and sufficient condition for oscillation of the generalized Lienard equation[J]. Ann Mat Pura Appl, 1989,154(2): 223-230. [6] Jiang K, Han M. Boundedness of solutions and existence of limit cycles for a nonlinear system[J].Nonlinear Analysis TMA, 1996,36(12): 1995-2006. [7] LUO Ding-jun, WANG Xian, ZHU De-ming, et al. Bifurcation Theory and Methods of Dynamical Systems [M]. Singapore: World Scientific, 1997. [8] Sugie J, Da-Li Chen, Matsunaga H. On global asymptotic stability of systems of Lienard type[J].J Math Anal Appl, 1998,219(1):140-164. [9] Villari G, Zanolin F. On a dynamical system in the Lienard plane: Necessary and sufficient conditions for the intersection with the vertical isocline and applications[J]. Funkcial Ekvac, 1990,33(1):19-38. |