@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/