@article{EJDE_2009__2009__a105,
     author = {Zhuang,  Rong-Kun},
     title = {Annulus oscillation criteria for second order nonlinear elliptic differential equations with damping},
     journal = {Electronic journal of differential equations},
     year = {2009},
     volume = {2009},
     zbl = {1177.35083},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2009__2009__a105/}
}