@article{VMJ_2007_9_1_a3,
     author = {G. Ya. Grabarnik and A. A. Katz and L. A. Shwartz},
     title = {On non-commutative ergodic type theorems for free finitely generated semigroups},
     journal = {Vladikavkazskij matemati\v{c}eskij \v{z}urnal},
     pages = {38--47},
     year = {2007},
     volume = {9},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/VMJ_2007_9_1_a3/}
}