@book { MarketingkonzeptionzurProdukteinfhrung,
    title = "Marketingkonzeption zur Produkteinführung",
    author = "Bettina {Bulau}",
    year = "1997",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832400316",
    url = "https://m.diplom.de/document/215989"
}