@article{EJDE_2003__2003__a103,
     author = {Raffoul,  Youssef N.},
     title = {Periodic solutions for neutral nonlinear differential equations with functional delay},
     journal = {Electronic journal of differential equations},
     year = {2003},
     volume = {2003},
     zbl = {1054.34115},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2003__2003__a103/}
}