@book { StrukturundEntwicklungderBevlkerungderBRD,
    title = "Struktur und Entwicklung der Bevölkerung der BRD",
    author = "Sandra {Hoffmann}",
    year = "2002",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638144704",
    url = "https://www.hausarbeiten.de/document/7119"
}