@book { NachhaltigerEnergietrgerBiodiesel,
    title = "Nachhaltiger Energieträger Biodiesel?",
    author = "Felix {Kaup}",
    year = "2005",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832491956",
    url = "https://m.diplom.de/document/224321"
}