Constraints on Cosmological Parameters from the Analysis of the Cosmic   Lens All Sky Survey Radio-Selected Gravitational Lens Statistics
  We derive constraints on cosmological parameters and the properties of the lensing galaxies from gravitational lens statistics based on the final Cosmic Lens All Sky Survey (CLASS) data. For a flat universe with a classical cosmological constant, we find that the present matter fraction of the critical density is $\Omega_{\rm m}=0.31^{+0.27}_{-0.14}$ (68%) $^{+0.12}_{-0.10}$ (systematic). For a flat universe with a constant equation of state for dark energy $w = p_x({pressure})/\rho_x({energy density})$, we find $w < -0.55^{+0.18}_{-0.11}$ (68%). 
K.-H. Chae, A.D. Biggs, R.D. Blandford, I.W.A. Browne, A.G. de Bruyn,   C.D. Fassnacht, P. Helbig, N.J. Jackson, L.J. King, ...