4Marcelo A S Neves, Claudio A Rodn' guez, On unstable ship motions resulting from strong non-linear coupling[J]. Ocean Engineering, 2006, 33: 1853-1883.
5Aryanpour M, Ghorashis M. Heave and pitch motion of a ship due to moving masses and forces[J], Journal of Sound and Vibration, 2001, 241(2): 185-195.