@article{Ritschel:2008:ISM,
   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 Trans. Graph. (Proc. of SIGGRAPH ASIA 2008)},
   volume  = 27,
   number  = 5,
   year    = {2008}
}