@article{SM_1991_68_1_a10,
     author = {I. V. Abramov and E. A. Roganov},
     title = {Quasiconformal homotopies of elementary space mappings},
     journal = {Sbornik. Mathematics},
     pages = {205--212},
     year = {1991},
     volume = {68},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1991_68_1_a10/}
}