@article{MAN_1922__85_158907,
     author = {C. Carath\'eodory},
     title = {\"Uber die kanonischen {Ver\"anderlichen} in der {Variationsrechnung} der mehrfachen {Integrale}},
     journal = {Mathematische Annalen},
     pages = {78--88},
     publisher = {mathdoc},
     volume = {85},
     year = {1922},
     zbl = {48.0586.03},
     url = {http://geodesic.mathdoc.fr/item/MAN_1922__85_158907/}
}