@book { EffizienteGestaltungvonvirtualcommunities,
    title = "Effiziente Gestaltung von virtual communities",
    author = "Stephan Franz {Furtner}",
    year = "2002",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832453503",
    url = "https://m.diplom.de/document/220914"
}