@book { OnlineMarketingimMittelstand,
    title = "Online-Marketing im Mittelstand",
    author = "Arndt {Ihln}",
    year = "2007",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638616683",
    url = "https://www.hausarbeiten.de/document/70612"
}