@article{FPM_2005_11_1_a13,
     author = {O. D. Viktorova},
     title = {On the multiply connectedness of level lines $m\pi$ of $n$-soliton solutions of the {sine-Gordon} equation},
     journal = {Fundamentalʹna\^a i prikladna\^a matematika},
     pages = {255--263},
     publisher = {mathdoc},
     volume = {11},
     number = {1},
     year = {2005},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FPM_2005_11_1_a13/}
}