@Article{schwan02a,
  author = 	 "T. Schaub and K. Wang",
  title = 	 "A semantic framework for preference handling in answer set programming",
  journal = 	 "Theory and Practice of Logic Programming",
  year = 	 2003,
  volume =	 3,
  number =	 "4-5",
  pages =	 "569-607",
  note =	 ""
}