@inbook{RVHE2006,
author = "C. Romero and S. Ventura and C{\'e}sar Herv{\'a}s-Mart{\'i}nez and P.G. Espejo",
address = " ",
chapter = " ",
edition = " ",
month = " ",
number = " ",
pages = "171--188",
publisher = "WitPress",
series = " ",
title = " {R}ule {M}ining with {GBGP} to improve web-based adaptive educational systems",
type = " ",
volume = " ",
year = "2006",
}