Christian Prause Stefaan Ternier Tim de Jong Stefan Apelt Marius Scholten Martin Wolpers Markus Eisenhauer Bram Vandeputte Marcus Specht Erik Duval Unifying Learning Object Repositories in MACE. 2007 LODE http://ceur-ws.org/Vol-311/paper01.pdf conf/ectel/2007lode db/conf/ectel/lode2007.html#PrauseTJASWEVSD07