Existence and uniqueness of periodic solutions for a kind of Liénard equation with a deviating argument

In this work, we use the coincidence degree theory to establish new results on the existence and uniqueness of TT-periodic solutions for a kind of Liénard equation with a deviating argument of the form x″(t)+f(x(t))x′(t)+g(t,x(t−τ(t)))=p(t).x″(t)+f(x(t))x′(t)+g(t,x(t−τ(t)))=p(t).