@article{10_1090_S0894_0347_1993_1212243_2,
     author = {Wallach, Nolan R.},
     title = {Invariant differential operators on a reductive {Lie} algebra and {Weyl} group representations},
     journal = {Journal of the American Mathematical Society},
     pages = {779--816},
     publisher = {mathdoc},
     volume = {06},
     number = {4},
     year = {1993},
     doi = {10.1090/S0894-0347-1993-1212243-2},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-1993-1212243-2/}
}