Invariant tori for a reversible oscillator with a nonlinear damping and periodic forcing term (Q2492449)

Using a result owing to \textit{B. Liu} and \textit{J. Song} [Acta Math. Sin., Engl. Ser. 20, 15--24 (2004; Zbl 1057.37054)], the author deals with the boundedness of all solutions of the reversible system \[ x^{\prime\prime}+f(x,x^\prime)+\omega^2x+\phi(x)=p(t),\qquad ^\prime=\frac{d}{dt}\;, \] where \(\omega\) is a positive constant, \(f(x,y),\phi(x)\) and \(p(t)\) are smooth functions, and \(p(t)=p(t+2\pi)\).