@article{DAN_1963_149_4_a6,
     author = {\`E. R. Rozendorn},
     title = {The isolated singular point on a surface with regular metric and negative curvature},
     journal = {Doklady Akademii Nauk},
     pages = {780--783},
     publisher = {mathdoc},
     volume = {149},
     number = {4},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_149_4_a6/}
}