Ramon Zatarain-Cabada Maria Lucia Barrón-Estrada Leopoldo Zepeda-Sánchez Fernando Vega-Juárez Authoring Learning Objects for Web-Based Intelligent Tutoring Systems. 66-77 2007 ICWL http://dx.doi.org/10.1007/978-3-540-78139-4_7 conf/icwl/2007 db/conf/icwl/icwl2007.html#Zatarain-CabadaBZV07