@article{MAN_1959__138_160708,
     author = {K. J\"orgens},
     title = {\"Uber die nichtlinearen {Wellengleichungen} der mathematischen {Physik.}},
     journal = {Mathematische Annalen},
     pages = {179--202},
     publisher = {mathdoc},
     volume = {138},
     year = {1959},
     zbl = {0092.09701},
     url = {http://geodesic.mathdoc.fr/item/MAN_1959__138_160708/}
}