@article{AM2_1978__17_136745,
     author = {Ian M. Anderson},
     title = {Tensorial {Euler-Lagrange} expressions and conservation laws.},
     journal = {Aequationes mathematicae},
     pages = {255--291},
     year = {1978},
     volume = {17},
     zbl = {0418.49041},
     url = {http://geodesic.mathdoc.fr/item/AM2_1978__17_136745/}
}