@article{ImplementingTest,
  author = "Richard Gault and Peter Jeavons",
  journal = "Constraints",
  pages = "139--160",
  title = "Implementing a test for tractability",
  url = "http://www.kluweronline.com/article.asp?PIPS=5268458",
  volume = "9",
  year = "2004",
}