@book { AufbaulangfristigerundprofitablerKundenbeziehungendurchCustomerRelationshipManagement,
    title = "Aufbau langfristiger und profitabler Kundenbeziehungen durch Customer Relationship Management",
    author = "Philipp {Langbehn}",
    year = "2003",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638223584",
    url = "https://www.hausarbeiten.de/document/17914"
}