@Article{Ritschel:2008:SIGA,
  author  = {Tobias Ritschel and Thorsten Grosch and Min H. Kim and Hans-Peter Seidel and Carsten Dachsbacher and Jan Kautz},
  title   = {Imperfect Shadow Maps for Efficient Computation of Indirect Illumination},
  journal = {ACM Transactions on Graphics (Proc. SIGGRAPH Asia 2008)},
  year    = {2008},
  volume  = {27},
  number  = {5},
  pages   = {129:1--8},
  doi     = "1409060.1409082",
  URL     = "http://dl.acm.org/citation.cfm?doid=1409060.1409082"
}