@book { KnigLudwigIvonBayernundseineZeitgenossen,
    title = "König Ludwig I. von Bayern und seine Zeitgenossen",
    author = "Wilhelm {Liebhart}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1095370"
}