Michael D. Kickmeier-Rust Dietrich Albert The ELEKTRA Ontology Model: A Learner-Centered Approach to Resource Description. 78-89 2007 ICWL http://dx.doi.org/10.1007/978-3-540-78139-4_8 conf/icwl/2007 db/conf/icwl/icwl2007.html#Kickmeier-RustA07