@article{MAN_1941__118_160103,
     author = {J. von Schwarz},
     title = {Eine {Methode} zur {Verallgemeinerung} der gew\"ohnlichen {Differentialgleichungen}},
     journal = {Mathematische Annalen},
     pages = {497--517},
     publisher = {mathdoc},
     volume = {118},
     year = {1941},
     zbl = {68.0454.03},
     url = {http://geodesic.mathdoc.fr/item/MAN_1941__118_160103/}
}