Effects of voids on the reconstruction of the equation of state of Dark   Energy
  We quantify the effects of the voids known to exist in the Universe upon the reconstruction of the dark energy equation of state $w$. We show that the effect can start to be comparable with some of the other errors taken into account when analysing supernova data, depending strongly upon the low redshift cut-off used in the sample. For the supernova data alone, the error induced in the reconstruction of $w$ is much larger than the percent level. When the Baryonic Acoustic Oscillations and the CMB data are included in the fit, the effect of the voids upon the determination of $w$ is much lessened, but is not much smaller than some of the other errors taken into consideration when performing such fits. 
Arnaud de Lavallaz and Malcolm Fairbairn
astro-ph.CO