@article{EJDE_2010__2010__a109,
     author = {Dai, Jinchun and Li, Yongkun and Zhang, Tianwei},
     title = {Positive periodic solutions for nonautonomous impulsive neutral functional differential systems with time-varying delays on time scales},
     journal = {Electronic Journal of Differential Equations},
     publisher = {mathdoc},
     volume = {2010},
     year = {2010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2010__2010__a109/}
}