@book { KundenbindungsmanagementinderSpitzenhotellerie,
    title = "Kundenbindungsmanagement in der Spitzenhotellerie",
    author = "Andrea {Waskönig}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832471750",
    url = "https://m.diplom.de/document/222480"
}