@article{zz09ipl,
  title = "A note on some collapse results of valued constraints",
  author = "Bruno Zanuttini and Stanislav \v{Z}ivn\'y",
  year = "2009",
  journal = "Information Processing Letters",
  number = "11",
  pages = "534--538",
  url = "http://zivny.cz/publications/zz09ipl-preprint.pdf",
  volume = "109",
  doi = "10.1016/j.ipl.2009.01.018",
}