TY - JOUR T1 - A comparative study of dropout rates and causes for two different distance education courses JF - The International Review of Research in Open and Distributed Learning Y1 - 2004 A1 - Christos J. Pierrakeas A1 - Xeno, Michalis A1 - Panagiotakopoulos, Christos A1 - Vergidis, Dimitris VL - 5 ER -