@book { DerKampfumGlubigeundKinder,
    title = "Der Kampf um Gläubige und Kinder",
    author = "Volker {Speth}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1110735"
}