@book { MarktpotenzialefrMBusinessmitUMTS,
    title = "Marktpotenziale für M-Business mit UMTS",
    author = "Ingo {Rutz}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832444822",
    url = "https://m.diplom.de/document/220084"
}