4Omari P Zanolin F. On the existence of periodic solutions of force Lienard differential eqnations[J]. Nonlinear Analysis, 1987;11(2):275-284
5Zhang Bo. Periodic solutions of the retarted Lienard - equation[J]. Ann Math Pura Appl, 1997;172(4):25-42
6Gaines R E, Mawhin J L. Coincidence degree, and Nonlinear Differential Equaations[M], New York:Springer-Verlag, 1977
7康蒂 黄启昌译.非线性微分方程[M].北京:科学出版社,1983..
8Wang G G, Cheng S S. A priori bounds for periodic solutions of a delay Rayleigh equation [ J ]. Appl Math Comput, 1999,12 (3) : 41 -44.
9Wang X M. On the existence of periodic solutions for a class of Rayleigh type p - Laplacian equations with deviating arguments [ J ]. Nonlinear Oscillations,2012,15 (3) :331 - 336.
