Periodic solutions for a kind of Liénard equation with a deviating argument ✩

By means of continuation theorem of coincidence degree theory, we study a kind of Liénard equation with a deviating argument as follows x (t )+ f x(t) x (t )+g x t − τ t,x(t) = e(t ). Some new results on the existence of periodic solutions are obtained.  2003 Elsevier Inc. All rights reserved.