7Brayton R. Bifurcation of periodic solutions in a nonlinear difference-differential equations of neutral type[J]. Quart Appl Math, 1006 ,ⅩⅩⅣ(3) : 215-224.
8Nayfeh A H. Introduction to Porturbation Techniques[M]. John Wiley & Sons,1981.
9Plaut R H, Hsieh J C. Nonlinear structural vibrations involving a time delay in damping[J]. Journal of Sound and Vibration, 1987,117 (3) : 497-510.
10Plaut R H, Hsieh J C. Chaosin in mechanism with time delay under parametric and external[J]. Journal of Sound and Vibration, 1987,11 (4): 73-90.
