@article{EJDE_2010__2010__a48,
     author = {Li, Yongkun and Zhang, Tianwei and Suo, Jianfeng},
     title = {Existence of three positive periodic solutions for differential systems with feedback controls 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__a48/}
}