@book { DasAbzugsverbotdes3cEStG,
    title = "Das Abzugsverbot des §3c EStG",
    author = "Stefan {Decker}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832469061",
    url = "https://m.diplom.de/document/222245"
}