@book { ManagementproduktbegleitenderDienstleistungen,
    title = "Management produktbegleitender Dienstleistungen",
    author = "Marcus {Zimmermann}",
    year = "2008",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836613293",
    url = "https://m.diplom.de/document/225801"
}