References
- James , E. M. and Llyod , N. G. 1991 . A Cubic System with Eight Small-Amplitude Limit Cycles . IMA J. of Appl. Math , 47 : 163 – 171 .
- Dongming , Wang . 1990 . A Class of Cubic Differential Systems with 6-Tuple Focus . J. Differential Equations , 87 : 305 – 315 .
- Li , Liu , Zhengyi , Lu and Dongming , Wang . 1990 . On the Structure of the Lasalle's Invariant Set for Lotka-Volterra System . Scientia Sinica , 10 : 1023 – 1028 .
- Guckenheimer , J. and Holmes , P. 1986 . Nonlinear Oscillations, Dynamical Systems and Bifurcations of Vector Fields , New York Berlin, Heidelberg, Tokyo : Springer-Verlag .
- Levi M. Qualitative Analysis of the Periodically Forced Relaxation Oscillation Ph.D thesis New York University 1978
- Littlewood , J. E. 1957 . On Nonlinear Differential Equations of the Second Order . Acta Math., London , 98 : 1 – 110 .
- Zhiming , Zheng . 1990 . Qualitative Analysis of Van der Pol Type Equation with Periodic Forcing Term . Acta , 6 ( 3 ) : 243 – 256 .
- 1980 . Lyapunov Characteristic Exponents for Smooth Dynamical Systems and for Hamiltonian Systems; A Method for Computing All of Them, Meccanica , 6 ( 3 ) : 9 – 30 .
- Buchberger , B. and Bases , Grobner . 1985 . Algorithmic Method in Polynomial Ideal Theory, in Recent Trends in Multidimensional Systems Theory , Edited by: Bose , N. K. D. Reidel Publ. Comp .
- Tsiin , Wu Wen . 1986 . Basic Principle of Mechanical Theorem Proving in Elementary Geometries . J. , 2 ( 4 ) : 221 – 252 .
- Knuth , D. E. and Bendix , P. B. 1970 . Simple Word Problems in Universal Algebras , Edited by: Leach , J.. 263 – 297 . New York : Pergamon Press .