@article{EJDE_2002__2002__a13,
     author = {Bensedik,  Ahmed and Bouchekif,  Mohammed},
     title = {On certain nonlinear elliptic systems with indefinite terms},
     journal = {Electronic journal of differential equations},
     year = {2002},
     volume = {2002},
     zbl = {1068.35507},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2002__2002__a13/}
}