@article{EJDE_2007__2007__a4,
     author = {Xia,  Li and Yao,  Zhengan},
     title = {Positive solutions for a class of singular boundary-value problems},
     journal = {Electronic journal of differential equations},
     year = {2007},
     volume = {2007},
     zbl = {1117.34030},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2007__2007__a4/}
}