@book { DasFalajSystemimSultanatOman,
    title = "Das Falaj System im Sultanat Oman",
    author = "Siegrun Samira {Rengert}",
    year = "1997",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832401894",
    url = "https://m.diplom.de/document/216139"
}