Correcting for lensing bias in the Hubble diagram
  Gravitational lensing will cause a dispersion in the Hubble diagram for high redshift sources. This effect will introduce a bias in the cosmological parameter determination using the distance-redshift relation for Type Ia supernovae. In this note we show how one can diagnose and correct for this bias when doing precision cosmology with supernovae. 
R. Amanullah, E. Mortsell and A. Goobar