@book { ZieleundInstrumentedesAfterSalesService,
    title = "Ziele und Instrumente des After Sales Service",
    author = "Sebastian {Baethge}",
    year = "2007",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638011471",
    url = "https://www.hausarbeiten.de/document/85207"
}