@article{MZ_1932__34_168334,
     author = {M., Kerner},
     title = {Minimaxeigenschaft der offenen und geschlossenen {Extremalen}},
     journal = {Mathematische Zeitschrift},
     pages = {645--667},
     publisher = {mathdoc},
     volume = {34},
     year = {1932},
     zbl = {0003.40102},
     url = {http://geodesic.mathdoc.fr/item/MZ_1932__34_168334/}
}