Wouter R. van Joolingen Lars Bollen Heinz Ulrich Hoppe Ton de Jong CIEL, architectures for collaborative inquiry and experiential learning. 308-312 2007 conf/icalt/2007 ICALT http://doi.ieeecomputersociety.org/10.1109/ICALT.2007.90 db/conf/icalt/icalt2007.html#JoolingenBHJ07