@book { MusiktauschbrsenimInternet,
    title = "Musiktauschbörsen im Internet",
    author = "Thomas {Schäfer}",
    year = "2005",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832486488",
    url = "https://m.diplom.de/document/223842"
}