@book { IstdieEurozoneeinoptimalerWhrungsraum,
    title = "Ist die Eurozone ein optimaler Währungsraum?",
    author = "Tobias {Kahler}",
    year = "2009",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    url = "https://m.diplom.de/document/227123"
}