%0 Journal Article
%A N. Abe
%A Y. Nakanishi
%A S. Yamagushi
%T Circles and spheres in pseudo-Riemannian geometry.
%J Aequationes mathematicae
%D 1990
%P 134-145
%V 39
%N 2-3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/AM2_1990__39_2-3_137345/
%F AM2_1990__39_2-3_137345