@article{Noether1971InvariantVP,
title={Invariant Variation Problems},
author={Emmy Noether and M. Tavel},
journal={Transport Theory and Statistical Physics},
year={1971},
volume={1},
pages={186-207}
}

Abstract The problems in variation here concerned are such as to admit a continuous group (in Lie's sense); the conclusions that emerge for the corresponding differential equations find their most general expression in the theorems formulated in Section I and proved in following sections. Concerning these differential equations that arise from problems of variation, far more precise statements can be made than about arbitrary differential equations admitting of a group, which are the subject of… Expand