%0 Journal Article
%A Russell Lyons
%A Mikaël Pichot
%A Stéphane Vassout
%T Uniform non-amenability, cost, and the first $\ell^2$-Betti number
%J Groups, geometry, and dynamics
%D 2008
%P 595-617
%V 2
%N 4
%U http://geodesic.mathdoc.fr/articles/10.4171/ggd/49/
%R 10.4171/ggd/49
%F 10_4171_ggd_49