@article{GDZPPN002401800,
title = {Canonical Variables and Geodesic Fields for the Calculus of Variations of Multiple Integrals in Parametric.},
journal = {Mathematische Zeitschrift},
volume = {105},
year = {1968},
pages = {16-27},
zbl = {0162.43202},
url = {http://dml.mathdoc.fr/item/GDZPPN002401800}
}
Martin, D.H. Canonical Variables and Geodesic Fields for the Calculus of Variations of Multiple Integrals in Parametric.. Mathematische Zeitschrift, Tome 105 (1968) pp. 16-27. http://gdmltest.u-ga.fr/item/GDZPPN002401800/