Contact geometry and non-linear differential equations

KUŠNER, Aleksej Gur'jevič - LYČAGIN, Valentin Vasil'jevič - RUBCOV, Vladimir Nikolajevič. Contact geometry and non-linear differential equations. First published. Cambridge, UK ; New York : Cambridge University Press, 2007. xxi, 496 stran. Encyclopedia of mathematics and its applications ; volume 101. ISBN 978-0-521-82476-7.