TY  - JOUR
AU  - B. E. Kantor
TI  - On~the problem of the normal image of a~complete surface of negative curvature
JO  - Sbornik. Mathematics
PY  - 1970
SP  - 197
EP  - 200
VL  - 11
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SM_1970_11_2_a4/
LA  - en
ID  - SM_1970_11_2_a4
ER  -