@inproceedings{DBLP:conf/ectel/AsteBCFMR07,
  author    = {Nicola Aste and
               Aldo Bongio and
               Stefano Ceri and
               Marco Fais and
               Maristella Matera and
               Alessandro Raffio},
  title     = {Model-Driven Design of VoIP Services for E-Learning},
  booktitle = {COOPER},
  year      = {2007},
  ee        = {http://ceur-ws.org/Vol-309/paper02.pdf},
  crossref  = {DBLP:conf/ectel/2007cooper},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}

@proceedings{DBLP:conf/ectel/2007cooper,
  editor    = {Stefano Ceri and
               Wolfgang Nejdl and
               Jan van Bruggen and
               Frans Van Assche},
  title     = {Proceedings of the 1st International Workshop on Collaborative
               Open Environments for Project-Centered Learning, COOPER-2007,
               Sissi, Lassithi - Crete Greece, 17 September, 2007},
  booktitle = {COOPER},
  publisher = {CEUR-WS.org},
  series    = {CEUR Workshop Proceedings},
  volume    = {309},
  year      = {2008},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}