@article{PMF_1931_38_1_a7,
     author = {Wundheiler, A.},
     title = {\"Uber die {Variationsgleichungen} f\"ur affine geod\"atische {Linien} und nichtholonome nichtkonservative dynamische {Systeme}},
     journal = {Prace Matematyczno-Fizyczne},
     pages = {129--147},
     publisher = {mathdoc},
     volume = {38},
     number = {1},
     year = {1931},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/PMF_1931_38_1_a7/}
}