@article{FPM_1996_2_1_a20,
     author = {U. U. Umirbaev},
     title = {On ranks of elements of free groups},
     journal = {Fundamentalʹna\^a i prikladna\^a matematika},
     pages = {313--315},
     publisher = {mathdoc},
     volume = {2},
     number = {1},
     year = {1996},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FPM_1996_2_1_a20/}
}