@article{Sintorn2008eg, 
  author =    {Erik Sintorn and Elmar Eisemann and Ulf Assarsson},
  title =     {Sample Based Visibility for Soft Shadows using Alias-free Shadow Maps},
  journal =   {Computer Graphics Forum (Proceedings of the Eurographics Symposium on Rendering 2008)},
  year =      {2008},
  pages =     {1285--1292},
  volume =    {27},
  number =    {4},
  publisher = {Eurographics Association}
}