@book { AfricaChallengesofMultilingualism,
    title = "Africa: Challenges of Multilingualism",
    author = "Claus {Altmayer} and Ekkehard {Wolff}",
    year = "2013",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-03725-8",
    url = "https://www.peterlang.com/document/1046776"
}