@book { IstDeutschlandeinVitaminMangelland,
    title = "Ist Deutschland ein Vitamin-Mangelland?",
    author = "Sven-David {Müller}",
    year = "2015",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    url = "https://www.hausarbeiten.de/document/287329"
}