@article{Perkins:2009rH,
  author = "Perkins, Warren  and  Warrick, Edmund",
  title = "{Unitarity Methods For Massless One-Loop Amplitudes}",
  doi = "10.22323/1.070.0104",
  journal = "PoS",
  year = 2009,
  volume = "ACAT08",
  pages = "104"
}