@book { SystemwettbewerbversusHarmonisierunginEuropa,
    title = "Systemwettbewerb versus Harmonisierung in Europa",
    subtitle = "Am Beispiel des Arbeitsmarktes",
    author = "Claudia {Hafner}",
    year = "1999",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b14039",
    url = "https://www.peterlang.com/document/1068572"
}