@article{EJDE_2004__2004__a2,
     author = {Sun,  Jingan and Cui,  Yonghong},
     title = {Permanence of predator-prey system with infinite delay},
     journal = {Electronic journal of differential equations},
     year = {2004},
     volume = {2004},
     zbl = {1056.92050},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2004__2004__a2/}
}