Zacharias Lekkas Nikos Tsianos Panagiotis Germanakos Constantinos Mourlas George Samaras The Role of Affect in Personalized Learning. 629-633 2009 ICALT http://dx.doi.org/10.1109/ICALT.2009.203 conf/icalt/2009 db/conf/icalt/icalt2009.html#LekkasTGMS09