@article{10_1017_S0017089505002697,
     author = {L\"U, HAISHEN and O'REGAN, DONAL and AGARWAL, RAVI P.},
     title = {UPPER {AND} {LOWER} {SOLUTIONS} {FOR} {THE} {SINGULAR} {p-LAPLACIAN} {WITH} {SIGN} {CHANGING} {NONLINEARITIES} {VIA} {INEQUALITY} {THEORY}},
     journal = {Glasgow mathematical journal},
     pages = {439--460},
     year = {2005},
     volume = {47},
     number = {3},
     doi = {10.1017/S0017089505002697},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089505002697/}
}