@article{GDZPPN002340518,
title = {Variational principles for differential equations with symmetries and conservation laws. II. Polynomial differential equations.},
journal = {Mathematische Annalen},
volume = {302},
year = {1995},
pages = {627-654},
zbl = {0889.58085},
url = {http://dml.mathdoc.fr/item/GDZPPN002340518}
}
Anderson, Ian M.; Pohjanpelto, Juha. Variational principles for differential equations with symmetries and conservation laws. II. Polynomial differential equations.. Mathematische Annalen, Tome 302 (1995) pp. 627-654. http://gdmltest.u-ga.fr/item/GDZPPN002340518/