Periodic solutions of forced Liénard-type equations
The authors establish the existence of periodic solutions for forced Liénard-type equations \[ \ddot{x}+f_1(x)\dot{x}+f_2(x)\dot{x}^2+g(x)=e(t) \] under appropriate conditions based on Mawhin's coincidence degree theory and Borsuk's theorem.
scientific article; zbMATH DE number 2136211