@article{10_4064_ap85_2_4,
     author = {Qi-gui Yang and Sui Sun Cheng},
     title = {Kamenev type oscillation criteria for second
 order matrix differential systems with damping},
     journal = {Annales Polonici Mathematici},
     pages = {145--152},
     publisher = {mathdoc},
     volume = {85},
     number = {2},
     year = {2005},
     doi = {10.4064/ap85-2-4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap85-2-4/}
}