@book{Bielefeld:1443,
      author        = "Welthaus Bielefeld",
      title         = "{Handy-Welten. Globales Lernen am Beispiel der
                       Mobiltelefone (Mobile worlds. Global learning on the
                       example of mobile phones)}",
      publisher     = "Welthaus Bielefeld",
      year          = "2004",
}