[1] OU Zengqi,TANG Chunlei.Periodic and Subharmonic Solutions for a Class of Superquadratic Hamiltonian Systems[J].Nonlinear Analysis TMA,2004,58(3):245-258.
[2] TANG Chunlei.A Note on Periodic Solutions of Second Order Systems[J].Proc. Amer. Math. Soc.,2003,132:1 295-1 393.
[3] ZHANG Xingyong,TANG Xianhua.Periodic Solutions for an Ordinary p-Laplacian System[J].Taiwanese Journal of Mathematics,2011,15(3):1 369-1 396.
[4] JEAN MAWHIN.Critical Point Theory and Hamiltonian Systems[M].New York:Springer Verlag,1989.
[5] ZHAO Fukun,WU Xian.Existence of Periodic Solutions for Nonautonmous Second Order Systemswith Linear Nonlinearity[J].Nonlinear Anal.,2005,60(7):325-335.
[6] TANG Chunlei.Periodic Solutions for Second Order Systems with Sublinear Nonlinearity[J].Proceedings of the American Mathematical Society,1998,126:3 263-3 270.