@book { MafiainDeutschland,
    title = "Mafia in Deutschland",
    author = "Philipp {Berner}",
    year = "2011",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640975778",
    url = "https://www.hausarbeiten.de/document/176372"
}