@article{Nagakura:2012L2,
  author = "Nagakura, Hiroki",
  title = "{Constraints to the GRB central engine from jet penetrability to massive stars}",
  doi = "10.22323/1.152.0103",
  journal = "PoS",
  year = 2012,
  volume = "GRB 2012",
  pages = "103"
}