@article{MZ_1964__83_170228,
     author = {Gilbert Helmberg},
     title = {\"Uber die {Nichtexistenz} },
     journal = {Mathematische Zeitschrift},
     pages = {261--266},
     publisher = {mathdoc},
     volume = {83},
     year = {1964},
     zbl = {0122.29902},
     url = {http://geodesic.mathdoc.fr/item/MZ_1964__83_170228/}
}