@book { LandeskundeNord,
    title = "Landeskunde Nord",
    author = "Frank Thomas {Grub}",
    year = "2013",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-02690-0",
    url = "https://www.peterlang.com/document/1067464"
}