@article{MZ_1971__119_171507,
     author = {Joachim Weidmann},
     title = {Oszillationsmethoden f\"ur {Systeme} gew\"ohnlicher {Differentialgleichungen.}},
     journal = {Mathematische Zeitschrift},
     pages = {349--374},
     publisher = {mathdoc},
     volume = {119},
     year = {1971},
     zbl = {0206.10002},
     url = {http://geodesic.mathdoc.fr/item/MZ_1971__119_171507/}
}