@Conference{torre97b,
  author = "Torre, F. and Rouveirol C.",
  title = "Opérateurs naturels en Programmation Logique Inductive",
  booktitle = "12èmes Journées Françaises d'Apprentissage (JFA'97), Roscoff France",
  editor = "Soldano H.",
  pages = "53--64",
  month = "May",
  year = "1997"
}