Marc Alier Forment Enric Mayol María José Casañ Guerrero Jordi Piguillem Jeffrey W. Merriman Miguel Ángel Conde González Francisco J. García-Peñalvo Wouter Tebben Charles Severance Clustering Projects for eLearning Interoperability. 106-122 2012 18 J. UCS 1 http://dx.doi.org/10.3217/jucs-017-01-0106 db/journals/jucs/jucs18.html#FormentMGPMGGTS12