@book { DerKampfumGlubigeundKinder,
    title = "Der Kampf um Gläubige und Kinder",
    subtitle = "Das Mischehenwesen im Rheinland im 19. Jahrhundert",
    author = "Volker {Speth}",
    year = "2018",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b14524",
    url = "https://www.peterlang.com/document/1057426"
}