1. Nonlinear coupled of pitch and roll modes in ship motions;Nayfeh;Journal of Hydronautics,1973
2. Dynamic absorbers for an externally excited pendulum;Tondl;Journal of Sound and Vibration,2000
3. Passive Vibration Control;Mwad,1988
4. Fundamental of Vibrations;Meirovitch,2001
5. M. Eissa, Vibration control of non-linear mechanical system via a neutralizer, Electronic Bulletin No. 16, Faculty of Electronic Engineering Menouf, Egypt, July, 1999.