@book { ZeroLowerBoundIsitaproblemintheEuroArea,
    title = "Zero Lower Bound - Is it a problem in the Euro Area?",
    author = "Lars {Protze}",
    year = "2008",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836612241",
    url = "https://m.diplom.de/document/225735"
}