Elena Grigorescu Tali Kaufman Madhu Sudan 2-Transitivity Is Insufficient for Local Testability. 259-267 2008 IEEE Conference on Computational Complexity http://doi.ieeecomputersociety.org/10.1109/CCC.2008.31 conf/coco/2008 db/conf/coco/coco2008.html#GrigorescuKS08