@article{MZ_1974__140_172147,
     author = {Hartmut Pecher},
     title = {Die {Existenz} regul\"arer {L\"osungen} f\"ur {Cauchy-} und {Anfangs-Randwertprobleme} nichtlinearer {Wellengleichungen.}},
     journal = {Mathematische Zeitschrift},
     pages = {263--280},
     publisher = {mathdoc},
     volume = {140},
     year = {1974},
     zbl = {0287.35069},
     url = {http://geodesic.mathdoc.fr/item/MZ_1974__140_172147/}
}