@book { Absatzcontrolling,
    title = "Absatzcontrolling",
    author = "Merle {Seibold}",
    year = "2002",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832457662",
    url = "https://m.diplom.de/document/221226"
}