@article{MAN_1924__91_159043,
     author = {H. Kneser},
     title = {Die adiabatische {Invarianz} des {Phasenintegrals} bei einem {Freiheitsgrad}},
     journal = {Mathematische Annalen},
     pages = {155--160},
     publisher = {mathdoc},
     volume = {91},
     year = {1924},
     zbl = {51.0730.06},
     url = {http://geodesic.mathdoc.fr/item/MAN_1924__91_159043/}
}