Existence and uniqueness of periodic solutions for a kind of Duffing equation with two deviating arguments

In this paper, we use the coincidence degree theory to establish new results on the existence and uniqueness of T -periodic solutions for a kind of Duffing equation with two deviating arguments of the form x ″ + C x ′ ( t ) + g 1 ( t , x ( t − τ 1 ( t ) ) ) + g 2 ( t , x ( t − τ 2 ( t ) ) ) = p ( t ) .