@article{BAG_1984__17_138267,
     author = {Gerd Richter},
     title = {On a problem of {Kertesz} and {Stern}},
     journal = {Beitr\"age zur Algebra und Geometrie},
     pages = {111--114},
     publisher = {mathdoc},
     volume = {17},
     year = {1984},
     zbl = {0538.06006},
     url = {http://geodesic.mathdoc.fr/item/BAG_1984__17_138267/}
}