@book { BrandManagementundCRM,
    title = "Brand Management und CRM",
    author = "Robert {Brandl}",
    year = "2005",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832490973",
    url = "https://m.diplom.de/document/224255"
}