TY  - JOUR
AU  - Bolle, Philippe
TI  - Morse Index of Approximating Periodic Solutions for the Billiard Problem. Application to Existence Results
JO  - Canadian journal of mathematics
PY  - 1998
SP  - 497
EP  - 524
VL  - 50
IS  - 3
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CJM-1998-027-6/
DO  - 10.4153/CJM-1998-027-6
ID  - 10_4153_CJM_1998_027_6
ER  -