@article{LinkeTompitsWoltran2004,
  author    = {Linke, Thomas and Tompits, Hans and Woltran, Stefan},
  title     = {On Acyclic and head-cycle free nested logic programs},
  isbn      = {3-540-22671-01},
  year      = {2004},
  language  = {en}
}
@article{LinkeTompitsWoltran2004,
  author    = {Linke, Thomas and Tompits, Hans and Woltran, Stefan},
  title     = {On acyclic and head-cycle free nested logic programs},
  year      = {2004},
  language  = {en}
}