@book { FulfillmentalsInstrumentzurKundenbindungimDirektmarketing,
    title = "Fulfillment als Instrument zur Kundenbindung im Direktmarketing",
    author = "Arndt {Schmidtmayer}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832434403",
    url = "https://m.diplom.de/document/219108"
}