@book { MarketingConceptfortheFriedrichNaumannFoundation,
    title = "Marketing Concept for the Friedrich Naumann Foundation",
    subtitle = "On the Example of the Regional Office of Johannesburg, Republic of South Africa",
    author = "Michael {Henschke}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832467609",
    url = "https://m.diplom.de/document/221720"
}