@book { MobileDatendiensteinJapan,
    title = "Mobile Datendienste in Japan",
    author = "Markus {Radner}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832474164",
    url = "https://m.diplom.de/document/222701"
}