@Article{RodríguezPenabad02,
author = {Penabad, M. R. and Brisaboa, N. R. and Hernandez, H. J. and Paramá, J. R.},
title = {A general procedure to check conjunctive query containment},
journal = {Acta Informática},
address = {Berlin},
year = {2002},
pages = {489-529}
}