@book { DieBeurteilungvonRatingagenturen,
    title = "Die Beurteilung von Ratingagenturen",
    author = "Jürgen {Kuttelwascher}",
    year = "1997",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832400279",
    url = "https://m.diplom.de/document/215985"
}