@article{MAN_1898__50_157867,
     author = {Kneser},
     title = {Zur {Variationsrechnung}},
     journal = {Mathematische Annalen},
     pages = {27--50},
     publisher = {mathdoc},
     volume = {50},
     year = {1898},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/MAN_1898__50_157867/}
}