@book { NelsonMandela,
    title = "Nelson Mandela",
    author = "Georg {Bacher}",
    year = "2012",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-00760-2",
    url = "https://www.peterlang.com/document/1044385"
}