Minglu Li Hongzi Zhu Yanmin Zhu PLANT: A Distributed Architecture for Personalized E-Learning. 20-30 2007 ICWL http://dx.doi.org/10.1007/978-3-540-78139-4_3 conf/icwl/2007 db/conf/icwl/icwl2007.html#LiZZ07