@book { StadtundAdelinFrauenfeld12501400,
    title = "Stadt und Adel in Frauenfeld 1250-1400",
    author = "Kurt {Burkhardt}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Lausanne, Switzerland",
    url = "https://www.peterlang.com/document/1070600"
}