@article{EJDE_2010__2010__a148,
     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},
     year = {2010},
     volume = {2010},
     zbl = {1203.34157},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2010__2010__a148/}
}