@Inproceedings{RodríguezBrisaboa98,
author = {Brisaboa, N. R. and Paramá, J. R. and Penabad, M. R. and Hernandez, H. J.},
title = {Built-in predicates in conjuctive queries: The contaiment problem},
booktitle = {Actas de las IV Jornadas de Informática},
address = {Las Palmas de Gran Canaria},
year = {1998},
pages = {497-505}
}