TY  - JOUR
AU  - Ya. B. Pesin
TI  - Geodesic flows on closed Riemannian manifolds without focal points
JO  - Izvestiya. Mathematics 
PY  - 1977
SP  - 1195
EP  - 1228
VL  - 11
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_1977_11_6_a3/
LA  - en
ID  - IM2_1977_11_6_a3
ER  -