@book { KohortenanalyseundMarktprognose,
    title = "Kohortenanalyse und Marktprognose",
    author = "Florian {Gerigk}",
    year = "2007",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836602945",
    url = "https://m.diplom.de/document/228840"
}