@book { RanulfcontraGeiger,
    title = "Ranulf contra Geiger",
    author = "Klaus {Rodax}",
    year = "2011",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-00636-0",
    url = "https://www.peterlang.com/document/1045754"
}