@article{DAN_1963_150_1_a10,
     author = {D. M. Smirnov},
     title = {On reduced free multi-operator groups},
     journal = {Doklady Akademii Nauk},
     pages = {44--47},
     publisher = {mathdoc},
     volume = {150},
     number = {1},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_150_1_a10/}
}