@article{IVM_2007_7_a8,
     author = {S. N. Tronin},
     title = {On retracts and retractions of free modules over graded rings},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {71--75},
     publisher = {mathdoc},
     number = {7},
     year = {2007},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_2007_7_a8/}
}