@article{MS2_1974__34_166350,
     author = {Arne Hole},
     title = {Invariant {Differential} {Operators} and {Polynomials} of {Lie} {Transformation} {Groups.}},
     journal = {Mathematica Scandinavica},
     pages = {109--123},
     publisher = {mathdoc},
     volume = {34},
     year = {1974},
     zbl = {0287.58008},
     url = {http://geodesic.mathdoc.fr/item/MS2_1974__34_166350/}
}