@article{GDZPPN002383365,
title = {On the Invariant Theory of Contact Transformations.},
journal = {Mathematische Zeitschrift},
volume = {56},
year = {1952},
pages = {415-427},
zbl = {0050.16304},
url = {http://dml.mathdoc.fr/item/GDZPPN002383365}
}
Davies, Evan T. On the Invariant Theory of Contact Transformations.. Mathematische Zeitschrift, Tome 56 (1952) pp. 415-427. http://gdmltest.u-ga.fr/item/GDZPPN002383365/