@book { Ketzerbekmpfungim13Jahrhundert,
    title = "Ketzerbekämpfung im 13. Jahrhundert",
    author = "Christian {Berwanger}",
    year = "2009",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640292547",
    url = "https://www.hausarbeiten.de/document/124030"
}