TY  - JOUR
AU  - N. Abe
AU  - Y. Nakanishi
AU  - S. Yamagushi
TI  - Circles and spheres in pseudo-Riemannian geometry.
JO  - Aequationes mathematicae
PY  - 1990
SP  - 134
EP  - 145
VL  - 39
IS  - 2-3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/AM2_1990__39_2-3_137345/
ID  - AM2_1990__39_2-3_137345
ER  -