Nikos Tsianos Panagiotis Germanakos Zacharias Lekkas Costas Mourlas George Samaras Marios Belk Working Memory Differences in E-Learning Environments: Optimization of Learners' Performance through Personalization. 385-390 2009 UMAP http://dx.doi.org/10.1007/978-3-642-02247-0_41 conf/um/2009 db/conf/um/umap2009.html#TsianosGLMSB09