@article{BAG_1990__30_138462,
     author = {M. Schmitz},
     title = {Zur {Zerlegung} von {Kreis\"uberdeckungen} {\"U(r,1)} der {Ebene} in zwei {Kreispackungen} ...(1) und q(r,1)},
     journal = {Beitr\"age zur Algebra und Geometrie},
     pages = {133--142},
     publisher = {mathdoc},
     volume = {30},
     year = {1990},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/BAG_1990__30_138462/}
}