@book { SiegelundSiegler,
    title = "Siegel und Siegler",
    subtitle = "Akten des 8. Internationalen Symposions für Byzantinische Sigillographie",
    author = "Claudia {Ludwig}",
    year = "2005",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1099406"
}