@article{GebserKaminskiSchaub2011,
  author    = {Martin Gebser and Roland Kaminski and Torsten H. Schaub},
  title     = {Complex optimization in answer set programming},
  journal   = {Theory and practice of logic programming},
  volume    = {11},
  number    = {3},
  pages     = {821 -- 839},
  doi       = {10.1017/S1471068411000329},
  year      = {2011},
}