@article{BAG_1986__22_138334,
     author = {Michael Schmitz},
     title = {\"Uberdeckungen der euklidischen {Ebene} durch zwei {Einheitskreispackungen}},
     journal = {Beitr\"age zur Algebra und Geometrie},
     pages = {39--52},
     publisher = {mathdoc},
     volume = {22},
     year = {1986},
     zbl = {0609.52009},
     url = {http://geodesic.mathdoc.fr/item/BAG_1986__22_138334/}
}