1. J.C. Snowdon, Vibration and Shock in Damped Mechanical Systems, Wiley, New York, 1968, pp. 333–365.
2. Some results on the nature of eigenvalues of discrete damped linear systems;Inman;American Society of Mechanical Engineers, Journal of Applied Mechanics,1980
3. A new method for finding symmetric form of asymmetric finite-dimensional dynamic systems;Ahmadian;American Society of Mechanical Engineers, Journal of Applied Mechanics,1987
4. Stability of rotating shafts with axial load and damping;Plaut,1977
5. Coupled torsional and transverse vibration of unbalanced rotor;Cohen;American Society of Mechanical Engineers, Journal of Applied Mechanics,1985