@inproceedings{torre97a,
  author = "Torre, F. and Rouveirol, C.",
  title = "Natural Ideal Operators in Inductive Logic Programming",
  booktitle = "9th European Conference on Machine Learning (ECML'97)",
  editor = "van Someren, M. and Widmer, G.",
  publisher = "Springer-Verlag",
  series="LNAI",
  volume = "1224",
  pages = "274-289",
  month = "April",
  year = "1997",
  location = "Prague, Czech Republic"
}