@book { VonderSteinzeitzumMittelalter,
    title = "Von der Steinzeit zum Mittelalter",
    author = "Birgit {Mangelsdorf}",
    year = "1999",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1088723"
}