@book { RatingfrdenMittelstandinDeutschland,
    title = "Rating für den Mittelstand in Deutschland",
    author = "Tobias {Edelmann}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832444945",
    url = "https://m.diplom.de/document/220095"
}