@book { DieWikingerinIrland,
    title = "Die Wikinger in Irland",
    author = "Christian {Knape}",
    year = "2010",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640612024",
    url = "https://www.hausarbeiten.de/document/150034"
}