@book { Altersteilzeit,
    title = "Altersteilzeit",
    subtitle = "Ein Modell der Personalentwicklung",
    author = "Frank {Knieps}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832444051",
    url = "https://m.diplom.de/document/220013"
}