@inproceedings{ijcai2009p33,
  title     = {Charting the Tractability Frontier of Mixed Multi-Unit Combinatorial Auctions},
  author    = {Fionda, Valeria and Greco, Gianluigi},
  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     = {134--138},
  year      = {2009},
  url       = {https://ijcai.org/proceedings/2009/33},
}