G. Ferraris, V. Maisonneuve, M. Lalanne, Prediction of the dynamic behavior of non symmetric coaxial co or counter-rotating rotors, Journal of Sound and Vibration, Vol. 195, No. 4, pp. 649-666, 1996.
 H. W. D. Chiang, C. N. Hsu, S. H. Tu, Rotor-bearing analysis for turbomachinery single- and dual-rotor systems, Journal of Propulsion and Power, Vol. 20, No. 6, pp. 1096-1104, 2004.
 Z. Fei, S. Tong, C. Wei, Investigation of the dynamic characteristics of a dual rotor system and its start-up simulation based on finite element method, Applied Physics & Engineering, Vol. 14, No. 4, pp. 268-280, 2013.
 Y. Yang, D. Cao, D. Wang, G. Jiang, Fixed-point rubbing characteristic analysis of a dual-rotor system based on the Lankarani-Nikravesh model, Mechanism and Machine Theory, Vol. 103, pp. 202-221, 2016.
 Y. Yang, D. Cao, T. Yu, D. Wang, C. Li, Prediction of dynamic characteristics of a dual-rotor system with fixed point rubbing – Theoretical analysis and experimental study, International Journal of Mechanical Sciences, Vol. 115, pp. 253-261, 2016.
 G. Schweitzer, E. Maslen, H. Bleuler, A. Traxler, M. Cole, P. Keogh, Magnetic bearings: theory, design, and application to rotating machinery, Springer, 2009.
 A. Chiba, T. Fukao, O. Ichikawa, M. Oshima, M. Takemoto, DG. Dorrell, Magnetic bearings and bearingless drives, London: Elsevier, 2005.
 J.C. Ji, A.Y.T. Leung, Non-linear oscillations of a rotor-magnetic bearing system under superharmonic resonance conditions, International Journal of Nonlinear Mechanics, Vol. 38, pp. 829-835, 2003.
 W. Zhang, M.H. Yao, X.P. Zhan, Multi-pulse chaotic motions of a rotor-active magnetic bearing system with time-varying stiffness, Chaos Solitons and Fractals, Vol. 27, pp. 175-186, 2006.
 W. Zhang, J.W. Zu, Transient, steady nonlinear responses for a rotor-active magnetic bearings system with time-varying stiffness, Chaos Solitons and Fractals, Vol. 38, pp. 1152-1167, 2008.
 J.I. Inayat-Hussain, Nonlinear dynamics of a magnetically supported rigid rotor in auxiliary bearings, Mechanism and Machine Theory, Vol. 45, pp. 1651-1667, 2010.
 J.I. Inayat-Hussain, Multiple attractors in the response of a flexible rotor in active magnetic bearings with geometric coupling, Journal of Physics: Conference Series, Vol. 96, pp. 1-7, 2008.
 J.I. Inayat-Hussain, Geometric coupling effects on the bifurcations of a flexible rotor response in active magnetic bearings, Chaos Solitons and Fractals, Vol. 41, pp. 2664-2671, 2009.
 S. Ghaedi, M. Ghayour, R. Tikani, Influence of weight parameter on chaotic vibration of flexible rotor supported by active magnetic bearings, Modares Mechanical Engineering, Vol. 16, No. 1, pp. 213-224, 2016. (in Persian)
 M.J Jang, C.K. Chen, Bifurcation analysis in flexible rotor supported by active magnetic bearings, International Journal of Bifurcation and Chaos, Vol. 11, No. 8, pp. 2163-2178, 2001.
 H. Xie, G.T. Flowers, L. Feng, C. Lawrence, Steady-state dynamic behavior of a flexible rotor with auxiliary support from a clearance bearing, Journal of Vibration and Acoustics, Vol. 121, pp. 78-83, 1999.
 R. Ebrahimi, M. Ghayour, H.M. Khanlo, Chaotic vibration analysis of a coaxial rotor system in active magnetic bearings and contact with auxiliary bearings, Journal of Computational and Nonlinear Dynamics, Vol. 12, 031012, 2016.
 Y. Ueda, Randomly transitional phenomena in the system governed by Duffing’s equation, Journal of Statistical Physics, Vol. 20, pp. 181-196, 1979.
 G. M. Jenkins, D. G. Watt, Spectral analysis and its applications, Michigan: Holden-Day, 1969.
 F. C. Moon, Chaotic vibration, an introduction for applied scientists and engineers, New Jersey: John Wiley, 2004.
 Y. Chen, Bifurcation and chaos in engineering, Springer, 1998.
 Xu. Jianxue, Some advances on global analysis of nonlinear systems, Chaos Solitons and Fractals, Vol. 39, pp. 1839–48, 2009.
 A. H. Nayfeh, B. Balachandran, Applied non-linear dynamics: analytical, computational and experimental methods, New York, Wiley, 1995.
 A. Wolf, J.B. Swift, H.L. Swinney, J.A. Vastano, Determining lyapunov exponents from a time series, Physica, Vol. 16, pp. 285-317, 1985.