@book { DemographischeEntwicklunginDeutschland,
    title = "Demographische Entwicklung in Deutschland",
    author = "Nicole {Böhmer}",
    year = "2007",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638586771",
    url = "https://www.hausarbeiten.de/document/67945"
}