@book { SpurenderdeutschenEinheit,
    title = "Spuren der deutschen Einheit",
    author = "Britta {Freis} and Marlon {Jopp}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1092027"
}