@book { Syrien,
    title = "Syrien",
    subtitle = "Eine Einführung in Politik und Gesellschaft",
    author = "Andreas {Dittmann} and Wolfgang {Gieler}",
    year = "2018",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b13100",
    url = "https://www.peterlang.com/document/1054535"
}