@article{MAN_1941__118_160112,
     author = {A. Dinghas},
     title = {Zum isoperimetrischen {Problem} f\"ur die nichteuklidischen {Geometrien}},
     journal = {Mathematische Annalen},
     pages = {636--686},
     publisher = {mathdoc},
     volume = {118},
     year = {1941},
     zbl = {0027.42903},
     url = {http://geodesic.mathdoc.fr/item/MAN_1941__118_160112/}
}