@conference{1587,
  author = {M. Conciatore and L. Antonelli and G. Stratta and Fabrizio Fiore and Rosalba Perna},
  title = {GRB environment properties through X and optical afterglow observations},
  year = {2005},
  url = {http://arxiv.org/pdf/astro-ph/0506448v1.pdf},
  note = {JILA Pub. 7706},
}