@article{MAN_1990__288_1_164763,
     author = {Thomas J. Enright and Mark G. Davidson},
     title = {Covariant differential operators.},
     journal = {Mathematische Annalen},
     pages = {731--739},
     publisher = {mathdoc},
     volume = {288},
     number = {1},
     year = {1990},
     zbl = {0723.22017},
     url = {http://geodesic.mathdoc.fr/item/MAN_1990__288_1_164763/}
}