Multiple periodic solutions of some Lienard equations with p-Laplacian

The existence, non-existence and multiplicity of solutions to periodic boundary value problems of Lienard type (vertical bar u'vertical bar(p-2)u')' + f(u)u' = g(u) = e(t) + s, u(0) - u(T) = 0 = u'(0) - u'(T), is discussed, where p > 1, f is arbitrary and g is assumed to be bounded, positive and g(+/-infinity) = 0. The function e is continuous on [0,T] with mean value 0 and s is a parameter.