Existence of periodic solutions for nonlinear Liénard systems
This paper deals with existence and multiplicity results for the periodic problem for a nonlinear Liénard system of the type \(x''(t) + {d \over dt} [\nabla F(x(t))] + g(x(t)) + h(t, x(t)) = e(t)\) under various conditions upon functions \(g,h\) and \(e\).
scientific article; zbMATH DE number 753682