@book { MitarbeiterundKundenzufriedenheit,
    title = "Mitarbeiter- und Kundenzufriedenheit",
    author = "Nicole {Kleinschmidt}",
    year = "2003",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638197601",
    url = "https://www.hausarbeiten.de/document/14328"
}