@book { KindermangelinDeutschland,
    title = "Kindermangel in Deutschland",
    subtitle = "Bevölkerungsökonomische Analysen und familienpolitische Lösungen",
    author = "Gunter {Steinmann}",
    year = "2007",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1103623"
}