@book { InstrumentedesOnlineMarketingsunterbesondererBercksichtigungdesSuchmaschinenMarketings,
    title = "Instrumente des Online-Marketings unter besonderer Berücksichtigung des Suchmaschinen-Marketings",
    author = "Andreas {Klein}",
    year = "2007",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638619820",
    url = "https://www.hausarbeiten.de/document/69453"
}