代表作
Auasiperiodic solutions of Duffing's equations, Nonlinear Analysis,33(1998),645-655.
Boundedness in nonlinear oscillations at resonance. J.D.E.153(1999),142-174
Boundedness of solutions ... J.D.E145(1998),119-144
Boundedness of solutions of nonlinear differential equations, J.D.E.144(1998),66-98
The stability of the equilibrium of reversible systems, Trans.A.M.S.351(1999),515-531
