@article{FPM_2003_9_1_a2,
     author = {I. N. Balaba and S. V. Zelenov and S. V. Limarenko and A. V. Mikhalev},
     title = {Density theorems for graded rings},
     journal = {Fundamentalʹna\^a i prikladna\^a matematika},
     pages = {27--49},
     publisher = {mathdoc},
     volume = {9},
     number = {1},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FPM_2003_9_1_a2/}
}