@article{MZM_2000_67_3_a6,
     author = {A. S. Oliinyk and V. I. Sushchanskii},
     title = {Free group of infinite unitriangular matrices},
     journal = {Matemati\v{c}eskie zametki},
     pages = {382--386},
     publisher = {mathdoc},
     volume = {67},
     number = {3},
     year = {2000},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2000_67_3_a6/}
}