@article{EJDE_2006__2006__a192,
     author = {Costa,  David G. and Tehrani,  Hossein and Yang,  Jianfu},
     title = {On a variational approach to existence and multiplicity results for semipositone problems},
     journal = {Electronic journal of differential equations},
     year = {2006},
     volume = {2006},
     zbl = {1120.35307},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2006__2006__a192/}
}