@book { ZurbisherigenundzuknftigenRolledereuropischenNationalstaaten,
    title = "Zur bisherigen und zukünftigen Rolle der europäischen Nationalstaaten",
    author = "Günter {Mardus}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1093402"
}