@book { ViralMarketingoderviraleWerbung,
    title = "Viral Marketing oder virale Werbung?",
    author = "Benjamin {Mayer}",
    year = "2008",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836621816",
    url = "https://m.diplom.de/document/226320"
}