@article{VMUMM_1983_4_a2,
     author = {S. V. Aleshin},
     title = {A free group of finite automata},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {12--14},
     year = {1983},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1983_4_a2/}
}