@book { DasInnovationssystem,
    title = "Das Innovationssystem",
    subtitle = "Eine Analyse zur Innovationsfähigkeit von Unternehmungen",
    author = "Michael {Greiling}",
    year = "1998",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1087349"
}