Paris Avgeriou Andreas Papasalouros Simos Retalis Patterns for Designing Learning Management Systems. 115-132 2003 EuroPLoP http://hillside.net/europlop/HillsideEurope/Papers/EuroPLoP2003/2003_AvgeriouEtAl_PatternsForDesigning.pdf conf/europlop/2003 db/conf/europlop/europlop2003.html#AvgeriouPR03