@book { WirksamkeitderMusterwiderrufsbelehrung,
    title = "Wirksamkeit der Musterwiderrufsbelehrung",
    author = "Carolina {Boxberger}",
    year = "2011",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-00352-9",
    url = "https://www.peterlang.com/document/1044289"
}