@article{MZ_1966__92_170558,
     author = {Karl Nickel},
     title = {Ein {Permanenzsatz} f\"ur nichtlineare {Limitierungsverfahren.}},
     journal = {Mathematische Zeitschrift},
     pages = {307--313},
     publisher = {mathdoc},
     volume = {92},
     year = {1966},
     zbl = {0138.04001},
     url = {http://geodesic.mathdoc.fr/item/MZ_1966__92_170558/}
}