@article{JRAM_1967__227_150807,
     author = {Rolf Walter},
     title = {\"Uber zweidimensionale parabolische {Fl\"achen} im vierdimensional affinen {Raum.} {I.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {178--208},
     year = {1967},
     volume = {227},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1967__227_150807/}
}