@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},
     publisher = {mathdoc},
     volume = {2004},
     year = {2004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2004__2004__a2/}
}