@book { DieWeltgesellschaft,
    title = "Die Weltgesellschaft",
    author = "Server {Purtov}",
    year = "2009",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640426980",
    url = "https://www.hausarbeiten.de/document/134689"
}