@article{KonczakSchaubLinke2003,
  author    = {Kathrin Konczak and Torsten H. Schaub and Thomas Linke},
  title     = {Graphs and colorings for answer set programming with prefernces : preliminary report},
  url       = {http://www.cs.uni-potsdam.de/wv/pdfformat/koschli03a.pdf},
  year      = {2003},
}