@inproceedings{NewTractableClasses,
  title = "New Tractable Classes From Old",
  author = "David Cohen and Peter Jeavons and Richard Gault",
  year = "2003",
  journal = "Constraints",
  note = "Earlier version appears in Proceedings of CP2000, Lecture Notes In Computer Science, 1894, 2000, pp. 160--171 : \url{http://link.springer.de/link/service/series/0558/bibs/1894/18940160.htm}",
  number = "8",
  pages = "263--282",
  doi = "10.1023/A:1025623111033",
}