@article{MAN_1872__5_156591,
     author = {Cayley},
     title = {On a theorem in {Covariants}},
     journal = {Mathematische Annalen},
     pages = {625--629},
     year = {1872},
     volume = {5},
     zbl = {04.0062.02},
     url = {http://geodesic.mathdoc.fr/item/MAN_1872__5_156591/}
}