@book { DerWertvonMarken,
    title = "Der Wert von Marken",
    author = "Marc {Hesse}",
    year = "2008",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836622141",
    url = "https://m.diplom.de/document/226332"
}