@article{CMUC_2000__41_3_a1,
     author = {Richman, Fred},
     title = {Smooth invariants and $\omega$-graded modules over $k[X]$},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {445--448},
     publisher = {mathdoc},
     volume = {41},
     number = {3},
     year = {2000},
     mrnumber = {1795075},
     zbl = {1038.16013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2000__41_3_a1/}
}