TY  - JOUR
AU  - A. L. Verner
TI  - On the extrinsic geometry of elementary complete surfaces with nonpositive curvature. I
JO  - Sbornik. Mathematics
PY  - 1967
SP  - 205
EP  - 224
VL  - 3
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SM_1967_3_2_a4/
LA  - en
ID  - SM_1967_3_2_a4
ER  -