@article{SM_1994_79_2_a12,
     author = {R. Ts. Musaelyan},
     title = {The existence of infinite polygons in a~two-dimensional metric of variable negative curvature},
     journal = {Sbornik. Mathematics},
     pages = {459--469},
     publisher = {mathdoc},
     volume = {79},
     number = {2},
     year = {1994},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1994_79_2_a12/}
}