@inproceedings{ijcai2009p73,
  title     = {On Solving Boolean Multilevel Optimization Problemse},
  author    = {Argelich, Josep and Lynce, Inês and Silva, João P. Marques},
  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     = {393--397},
  year      = {2009},
  url       = {https://ijcai.org/proceedings/2009/73},
}