BibTeX Entry: Hierarchical Penumbra Casting

@article{Laine2005eurographics,
  author =    {Samuli Laine and Timo Aila},
  title =     {Hierarchical Penumbra Casting},
  journal =   {Computer Graphics Forum},
  volume =    {24},
  number =    {3},
  year =      {2005},
  pages =     {313--322},
  publisher = {Eurographics Association and Blackwell Publishing Ltd},
}