TY  - JOUR
AU  - G. A. Kovaleva
TI  - Example of a surface that is homotopic to a tube and has a closed asymptotic line
JO  - Matematičeskie zametki
PY  - 1968
SP  - 403
EP  - 413
VL  - 3
IS  - 4
UR  - http://geodesic.mathdoc.fr/item/MZM_1968_3_4_a4/
LA  - ru
ID  - MZM_1968_3_4_a4
ER  -