9Cohen R,Porat I.Coupled Torsional and Transverse Vibration of Unbalanced Rotor.Transactions of the ASME,Journal of Applied Mechancis,1985,52(9):701-705.
10Diken H,Tadjbakhsh I G.Unbalance Response of Flexible Rotor Coupled with Torsion[J].Journal of Vibration,Acoustics,Stress,and Reliability in Design,1989,111(4):179-186.