%0 Journal Article
%A A. G. Kremlyov
%A Yu. G. Nikonorov
%T The signature of the Ricci curvature of left-invariant Riemannian metrics on four-dimensional Lie groups. The nonunimodular case
%J Matematičeskie trudy
%D 2009
%P 40-116
%V 12
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MT_2009_12_1_a2/
%G ru
%F MT_2009_12_1_a2