@book { DieErdlindustrieimNigerdelta,
    title = "Die Erdölindustrie im Nigerdelta",
    author = "Dennis {Kiefer}",
    year = "2001",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638987462",
    url = "https://www.hausarbeiten.de/document/100318"
}