@article{02065395, title = {Positive solutions for semipositone }, journal = {Portugaliae Mathematica. Nova S\'erie}, volume = {60}, year = {2003}, pages = {253-262}, zbl = {1055.34032}, language = {en}, url = {http://dml.mathdoc.fr/item/02065395} }
He, Xiaoming; Ge, Weigao. Positive solutions for semipositone . Portugaliae Mathematica. Nova Série, Tome 60 (2003) pp. 253-262. http://gdmltest.u-ga.fr/item/02065395/