@article{ADM_2010_10_1_a4,
     author = {T. Gu\'ed\'enon},
     title = {Projectivity and flatness over the graded ring of semi-coinvariants},
     journal = {Algebra and discrete mathematics},
     pages = {42--56},
     year = {2010},
     volume = {10},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ADM_2010_10_1_a4/}
}