@INPROCEEDINGS{sae15b-prole15,
  author={F. S\'aenz-P\'erez},
  title={{Restricted Predicates for Hypothetical Datalog}},
  booktitle={{XV Jornadas sobre Programaci\'on y Lenguajes, PROLE2015
(SISTEDES)}},
  month={September},
  year={2015}
  }