@inproceedings{ijcai2009p282,
  title     = {Optimal Symbolic Planning with Action Costs and Preferences},
  author    = {Edelkamp, Stefan and Kissmann, Peter},
  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     = {1690--1694},
  year      = {2009},
  url       = {https://ijcai.org/proceedings/2009/282},
}