@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/