TY  - JOUR
AU  - N. V. Efimov
AU  - È. G. Poznyak
TI  - Generalization of Hilbert's theorem on surfaces of constant negative curvature
JO  - Doklady Akademii Nauk
PY  - 1961
SP  - 509
EP  - 512
VL  - 137
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1961_137_3_a4/
LA  - ru
ID  - DAN_1961_137_3_a4
ER  -