TY  - JOUR
AU  - G. A. Utkin
TI  - Topological classification of non-singular fourth-order surfaces
JO  - Doklady Akademii Nauk
PY  - 1967
SP  - 40
EP  - 43
VL  - 175
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1967_175_1_a9/
LA  - ru
ID  - DAN_1967_175_1_a9
ER  -