@book { DieWirtschaftsproblemeKameruns,
    title = "Die Wirtschaftsprobleme Kameruns",
    author = "Detlef {Rettinger}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1086120"
}