@book { Schlsselqualifikationen,
    title = "Schlüsselqualifikationen",
    author = "M. {Kops}",
    year = "2001",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638995986",
    url = "https://www.hausarbeiten.de/document/101177"
}