@article{1183486087, author = {Allen, E. F.}, title = {The jacobian of a contact transformation}, journal = {Bull. Amer. Math. Soc.}, volume = {30}, number = {9-10}, year = {1924}, pages = { 335-338}, language = {en}, url = {http://dml.mathdoc.fr/item/1183486087} }
Allen, E. F. The jacobian of a contact transformation. Bull. Amer. Math. Soc., Tome 30 (1924) no. 9-10, pp. 335-338. http://gdmltest.u-ga.fr/item/1183486087/