1. An improved stability criterion of third-order non-linear differential equations;Agarwal;Journal of Sound and Vibration,1978
2. Nondineca Differential Equations;Struble,1974
3. State Space Analysis an Introduction;Timothy,1968
4. Stability by Liapunov's Direct Method;La Salle,1961
5. R.P. Agarwal (to be Submitted for publication) Journal of Sound and Vibration. On the stability of certain non-linear differential equations.