@article{DBLP:journals/tplp/SchaubW03,
  author = {Schaub, Torsten and Wang, Kewen},
  title = {A semantic framework for preference handling in answer set programming},
  journal = {{TPLP}},
  volume = {3},
  number = {4-5},
  pages = {569--607},
  year = {2003}
}