@article{yu2009perceptualillumination,
 author = {Yu I, Cox A, Kim MH, Ritschel T, Grosch T, Dachsbacher C, Kautz J},
 title = {Perceptual Influence of Approximate Visibility in Indirect Illumination},
 year = {2009},
 journal = {ACM Transactions on Applied Perception},
 volume = {6},
 number = {4},
}