@book { ChristentumundVerfassungsstaat,
    title = "Christentum und Verfassungsstaat",
    author = "Hubertus {Zilkens}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1108748"
}