@article{10_4064_ap86_1_4,
     author = {Rong-Kun Zhuang and Zheng-an Yao},
     title = {Some new oscillation criteria for second order 
elliptic equations with damping},
     journal = {Annales Polonici Mathematici},
     pages = {31--42},
     publisher = {mathdoc},
     volume = {86},
     number = {1},
     year = {2005},
     doi = {10.4064/ap86-1-4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap86-1-4/}
}