@book { OptimaleRessourcenallokationimKundenlebenszyklus,
    title = "Optimale Ressourcenallokation im Kundenlebenszyklus",
    author = "Oliver {Conze}",
    year = "2005",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832491567",
    url = "https://m.diplom.de/document/224283"
}