TY  - JOUR
AU  - M. M. Popov
TI  - On the Morse index calculation and the prolongation of the ray formulae beyond caustics
JO  - Zapiski Nauchnykh Seminarov POMI
PY  - 2015
SP  - 225
EP  - 235
VL  - 438
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/ZNSL_2015_438_a13/
LA  - ru
ID  - ZNSL_2015_438_a13
ER  -