@article{BAG_1983__16_138255,
     author = {O.-H. KELLER},
     title = {\"Uber die {,,Numeri} idonei},
     journal = {Beitr\"age zur Algebra und Geometrie},
     pages = {79--92},
     publisher = {mathdoc},
     volume = {16},
     year = {1983},
     url = {http://geodesic.mathdoc.fr/item/BAG_1983__16_138255/}
}