@article{MZ_1932__35_168346,
     author = {W., Haack},
     title = {Affine {Differentialgeometrie} der parabolischen {Strahlensysteme}},
     journal = {Mathematische Zeitschrift},
     pages = {66--79},
     publisher = {mathdoc},
     volume = {35},
     year = {1932},
     zbl = {0003.36302},
     url = {http://geodesic.mathdoc.fr/item/MZ_1932__35_168346/}
}