@InProceedings{	  dixoso97prov,
  author	= {J\"{u}rgen Dix and Mauricio Osorio},
  title		= {Provability {C}losures in {L}ogic {P}rogramming},
  editor	= {Instituto Politectico Nacional},
  pages		= {313--319},
  publisher	= {},
  booktitle	= {Proceedings of the International Symposium on Computer
		  Science in Mexico},
  year		= {1997}
}