@article{DAN_1976_227_1_a12,
     author = {M. I. Kratko},
     title = {The number of switchings that are necessary for the unblocking of a three-step commutator},
     journal = {Doklady Akademii Nauk},
     pages = {54--56},
     publisher = {mathdoc},
     volume = {227},
     number = {1},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1976_227_1_a12/}
}