@article{PORMA_1944__4_3_114622,
     author = {Hopf, Heinz},
     title = {Eine {Verallgemeinerung} bekannter {Abbildungs-und} �?berdeckungss\"atze},
     journal = {Portugaliae mathematica},
     pages = {129--139},
     publisher = {mathdoc},
     volume = {4},
     number = {3},
     year = {1944},
     mrnumber = {0011438},
     zbl = {0060.40612},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1944__4_3_114622/}
}