@inproceedings{Szeider11a,
 author = {Stefan Szeider},
 booktitle = {Proceedings of the 
Twenty-Fifth Conference on Artificial Intelligence, AAAI 2011},
 pages = {93-98},
 publisher = {AAAI Press, Menlo Park, California},
 title = {Limits of Preprocessing},
 url = {http://arxiv.org/abs/1104.5566v2},
 year = {2011}
}