@book { SponsoringalsBelowthelineKommunikation,
    title = "Sponsoring als Below-the-line-Kommunikation",
    author = "Katja {Metan}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832444853",
    url = "https://m.diplom.de/document/220087"
}