@article{EJDE_2006__2006__a30,
     author = {Cui,  Yujun and Zou,  Yumei},
     title = {Positive solutions of singular fourth-order boundary-value problems},
     journal = {Electronic journal of differential equations},
     year = {2006},
     volume = {2006},
     zbl = {1096.34012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2006__2006__a30/}
}