@inproceedings{ijcai2009p164,
  title     = {On Combinations of Binary Qualitative Constraint Calculi},
  author    = {Wölfl, Stefan and Westphal, Matthias},
  booktitle = {Proceedings of the Twenty-First International Joint Conference on
               Artificial Intelligence, {IJCAI-09}},
  publisher = {International Joint Conferences on Artificial Intelligence},
  editor    = {Hiroaki Kitano},
  pages     = {967--972},
  year      = {2009},
  url       = {https://ijcai.org/proceedings/2009/164},
}