@book { DieEuropischeWirtschaftsundWhrungsunion,
    title = "Die Europäische Wirtschafts- und Währungsunion",
    author = "Oliver {Schäfer}",
    year = "1999",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832414474",
    url = "https://m.diplom.de/document/217301"
}