TY  - JOUR
AU  - S. V. Buyalo
TI  - Closed geodesics on 2-dimensional orbifolds of nonpositive curvature
JO  - Algebra i analiz
PY  - 1989
SP  - 89
EP  - 109
VL  - 1
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/AA_1989_1_3_a3/
LA  - ru
ID  - AA_1989_1_3_a3
ER  -