Periodic solutions for a generalized -Laplacian equation

The existence and uniqueness of T -periodic solutions for the following boundary value problems with p -Laplacian: ( ϕ p ( x ′ ) ) ′ + f ( t , x ′ ) + g ( t , x ) = e ( t ) , x ( 0 ) = x ( T ) , x ′ ( 0 ) = x ′ ( T ) are investigated, where ϕ p ( u ) = ∣ u ∣ p − 2 u with p > 1 and f , g , e are continuous and are T -periodic in t with f ( t , 0 ) = 0 . Using coincidence degree theory, some existence and uniqueness results are presented.