@article{MZM_1973_14_2_a11,
     author = {E. V. Shikin},
     title = {On regular embedding integrally in $R^3$ of metrics of class $C^4$ of negative curvature},
     journal = {Matemati\v{c}eskie zametki},
     pages = {261--266},
     publisher = {mathdoc},
     volume = {14},
     number = {2},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1973_14_2_a11/}
}