@article{DAN_1996_349_5_a6,
     author = {N. N. Nefedov},
     title = {Two-dimensional contrast structures of step type: asymptotics,},
     journal = {Doklady Akademii Nauk},
     pages = {603--605},
     publisher = {mathdoc},
     volume = {349},
     number = {5},
     year = {1996},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1996_349_5_a6/}
}