@book { AntonProkeschOsten,
    title = "Anton Prokesch-Osten",
    subtitle = "Ein österreichischer Diplomat im Orient",
    author = "Muhammad {Omar}",
    year = "1993",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1080447"
}