@article{JRAM_1936__175_149966,
     author = {G. Haenzel},
     title = {Die {Geometrie} der linearen {Strahlenkongruenz.} {II.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {169--181},
     publisher = {mathdoc},
     volume = {175},
     year = {1936},
     zbl = {0014.17301},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1936__175_149966/}
}