@book { DiedeutscheVereinigungvonauengesehen,
    title = "Die deutsche Vereinigung von außen gesehen",
    author = "Ines {Lehmann}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1082834"
}