@article{JDM_1917__25_145499,
     author = {Heinrich Liebmann},
     title = {Die {Transformation} von {Variationsproblemen.}},
     journal = {Jahresbericht der Deutschen Mathematiker-Vereinigung},
     pages = {366--383},
     publisher = {mathdoc},
     volume = {25},
     year = {1917},
     zbl = {46.0767.01},
     url = {http://geodesic.mathdoc.fr/item/JDM_1917__25_145499/}
}