@article{10_4064_ap97_2_6,
     author = {Yongkun Li and Changzhao Li and Juan Zhang},
     title = {Three  periodic solutions for a class of
higher-dimensional functional differential equations with
impulses},
     journal = {Annales Polonici Mathematici},
     pages = {169--183},
     publisher = {mathdoc},
     volume = {97},
     number = {2},
     year = {2010},
     doi = {10.4064/ap97-2-6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap97-2-6/}
}