@article{JRAM_1929__160_149675,
     author = {M. Herzberger},
     title = {\"Uber die geometrische {Bedeutung} des {Rotationswinkels} in der {Strahlengeometrie.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {33--37},
     publisher = {mathdoc},
     volume = {160},
     year = {1929},
     zbl = {55.0441.08},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1929__160_149675/}
}