@book { MotivationderArbeitsgeneration50,
    title = "Motivation der Arbeitsgeneration 50+",
    author = "Sven {Geitner}",
    year = "2010",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783842804531",
    url = "https://m.diplom.de/document/228045"
}