Clustering Projects for eLearning Interoperability. - Marc Alier Forment; Enric Mayol; María José Casañ Guerrero; Jordi Piguillem; Jeffrey W. Merriman; Miguel Ángel Conde González; Francisco J. García-Peñalvo; Wouter Tebbens; Charles R. Severance (J. Univers. Comput. Sci., 2012)