@article{02113406,
title = {Oscillation and nonoscillation criteria for two-dimensional systems of linear ordinary differential equations.},
journal = {Georgian Mathematical Journal},
volume = {11},
year = {2004},
pages = {137-154},
zbl = {1064.34019},
language = {en},
url = {http://dml.mathdoc.fr/item/02113406}
}
Polák, L. Oscillation and nonoscillation criteria for two-dimensional systems of linear ordinary differential equations.. Georgian Mathematical Journal, Tome 11 (2004) pp. 137-154. http://gdmltest.u-ga.fr/item/02113406/