@article{MZM_1979_25_5_a14,
     author = {E. V. Shikin},
     title = {Isometric imbedding in $E^3$ of noncompact domains of nonpositive curvature},
     journal = {Matemati\v{c}eskie zametki},
     pages = {785--797},
     publisher = {mathdoc},
     volume = {25},
     number = {5},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1979_25_5_a14/}
}