@article{DAN_1986_286_5_a6,
     author = {N. A. Gusevskii and N. S. Zindinova},
     title = {A characterization of extended {Schottky} groups},
     journal = {Doklady Akademii Nauk},
     pages = {1054--1057},
     publisher = {mathdoc},
     volume = {286},
     number = {5},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1986_286_5_a6/}
}