%0 Journal Article
%A Bachir Bekka
%A Alexander Lubotzky
%T Lattices with  and lattices without spectral gap
%J Groups, geometry, and dynamics
%D 2011
%P 251-264
%V 5
%N 2
%U http://geodesic.mathdoc.fr/articles/10.4171/ggd/126/
%R 10.4171/ggd/126
%F 10_4171_ggd_126