@article{Ghisellini:2012h0,
  author = "Ghisellini, Gabriele",
  title = "{GRBs have preferred jet opening angles and bulk Lorentz factors}",
  doi = "10.22323/1.152.0015",
  journal = "PoS",
  year = 2012,
  volume = "GRB 2012",
  pages = "015"
}