@book { LotharsIIIKampfmitdenStaufern,
    title = "Lothars III. Kampf mit den Staufern",
    author = "Holger {Macht}",
    year = "2004",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832483852",
    url = "https://m.diplom.de/document/223575"
}