@article{JRAM_1977__292_151879,
     author = {Dieter Hoffmann},
     title = {Zum },
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {138--145},
     publisher = {mathdoc},
     volume = {292},
     year = {1977},
     zbl = {0347.28010},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1977__292_151879/}
}