Naimdjon Takhirov Ingeborg Sølvberg Trond Aalberg Organizing Learning Objects for Personalized eLearning Services. 384-387 2009 ECDL http://dx.doi.org/10.1007/978-3-642-04346-8_40 conf/ercimdl/2009 db/conf/ercimdl/ecdl2009.html#TakhirovSA09