TY  - JOUR
AU  - Demir N. Kupeli
TI  - On Conjugate and Focal Points in Semi-Riemannian Geometry.
JO  - Mathematische Zeitschrift
PY  - 1988
SP  - 569
EP  - 590
VL  - 198
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZ_1988__198_3_173944/
ID  - MZ_1988__198_3_173944
ER  -