@article{MZ_1974__138_172094,
     author = {Helmut Wielandt},
     title = {Kriterien f\"ur {Subnormalit\"at} in endlichen {Gruppen.}},
     journal = {Mathematische Zeitschrift},
     pages = {199--204},
     publisher = {mathdoc},
     volume = {138},
     year = {1974},
     url = {http://geodesic.mathdoc.fr/item/MZ_1974__138_172094/}
}