@book { KennzahlengesttzesKundenbeziehungsControlling,
    title = "Kennzahlengestützes Kundenbeziehungs-Controlling",
    author = "Thomas {Burgartz}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1105215"
}