1. T.J. Yang, Z.Q. Gu, Z.G. Liu, Z.Q. Wang: Journal of Vibration Engineering, Vol. 30 (2010) No. 6, p.149. (In Chinese).
2. Z.C. Hou, Y.X. Lao, Q.H. Lu: Journal of Sound and Vibration. vol. 317(2008) No. 22. p.591.
3. W.Y. Zhou, D.X. Li: Journal of Sound and Vibration. Vol. 331(2012)No. 14. p.2984.
4. H.B. Liu, S.H. Chen, Y.Q. Nie, R.D. Chu: Chinese Internal Combustion Engine Engineering, Vol. 13(1995)No. 2. p.148.
5. S.H. CHEN: Matrix perturbation theory structural dynamic design. (Science Publications, China 1987).