@article{01420704,
title = {Existence of conservation laws in nilpotent case.},
journal = {Acta Mathematica Universitatis Comenianae. New Series},
volume = {68},
year = {1999},
pages = {243-247},
zbl = {0940.35050},
language = {en},
url = {http://dml.mathdoc.fr/item/01420704}
}
Mehdi, M. Existence of conservation laws in nilpotent case.. Acta Mathematica Universitatis Comenianae. New Series, Tome 68 (1999) pp. 243-247. http://gdmltest.u-ga.fr/item/01420704/