@book { ZieleundMitteleuropischerIntegration,
    title = "Ziele und Mittel europäischer Integration",
    author = "Ulrich {Böttger}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1094300"
}