Tegmark M., D.J. Eisenstein, M.A. Strauss, D.H. Weinberg, M.R. Blanton, J.A. Frieman, M. Fukugita, J.E. Gunn, A.J.S. Hamilton, G.R. Knapp, and R.C. Nichol, Physical Review D 74, (2006).
and 
and 