@book { OccupationalpensionschemesinGermany,
    title = "Occupational pension schemes in Germany",
    subtitle = "Changes in the German landscape of old-age plans, cta model",
    author = "Peter {Schulz}",
    year = "2007",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836605236",
    url = "https://m.diplom.de/document/229005"
}