@article{ADM_2007_4_a11,
     author = {A. E. Radwan},
     title = {Filtered and graded {Procesi} extensions of rings},
     journal = {Algebra and discrete mathematics},
     pages = {131--137},
     year = {2007},
     number = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ADM_2007_4_a11/}
}