@book { GottfriedvonBouilloninderHistoriographie,
    title = "Gottfried von Bouillon in der Historiographie",
    author = "Gerhart {Waeger}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Lausanne, Switzerland",
    url = "https://www.peterlang.com/document/1069267"
}