@article{EJDE_2006__2006__a194,
     author = {Li, Zhixiang and Wang, Xiao},
     title = {Existence of positive periodic solutions for neutral functional differential equations},
     journal = {Electronic Journal of Differential Equations},
     publisher = {mathdoc},
     volume = {2006},
     year = {2006},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2006__2006__a194/}
}