@book { DasWiderrufsrechtdesVerbrauchers,
    title = "Das Widerrufsrecht des Verbrauchers",
    author = "Janko {Büßer}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1092201"
}