Contemporaneo. Lingua Standard (in Italian), Milan: Hoepli, ISBN 978-88-203-4552-5 Gregersen, Edgar A. (1977), Language in Africa, CRC Press, ISBN 0-677-04380-5...
Contemporaneo. Lingua Standard (in Italian), Milan: Hoepli, ISBN 978-88-203-4552-5 Gregersen, Edgar A. (1977), Language in Africa, CRC Press, ISBN 978-0-677-04380-7...