@article{01413878,
title = {Contact geometry of hyperbolic Monge-Amp\'ere equations.},
journal = {Lobachevskii Journal of Mathematics},
volume = {3},
year = {1999},
pages = {109-162},
zbl = {0938.35011},
language = {en},
url = {http://dml.mathdoc.fr/item/01413878}
}
Tchij, O.P. Contact geometry of hyperbolic Monge-Ampére equations.. Lobachevskii Journal of Mathematics, Tome 3 (1999) pp. 109-162. http://gdmltest.u-ga.fr/item/01413878/