@article{MAN_1935__110_159722,
     author = {W. Damk\"ohler},
     title = {\"Uber indefinite {Variationsprobleme}},
     journal = {Mathematische Annalen},
     pages = {230--283},
     publisher = {mathdoc},
     volume = {110},
     year = {1935},
     zbl = {60.0455.02},
     url = {http://geodesic.mathdoc.fr/item/MAN_1935__110_159722/}
}