@article{MZ_1926__25_167868,
     author = {L. Koschmieder},
     title = {Invarianten bei der {Variation} der {Integrale,} deren {Integranden} h\"ohere {Ableitungen} enthalten},
     journal = {Mathematische Zeitschrift},
     pages = {74--86},
     publisher = {mathdoc},
     volume = {25},
     year = {1926},
     zbl = {52.0504.02},
     url = {http://geodesic.mathdoc.fr/item/MZ_1926__25_167868/}
}