University of Cambridge ESOL Examinations. (2007). Official ielts practice materials. University of Cambridge ESOL Examinations.
Chicago-referens (17:e uppl.)University of Cambridge ESOL Examinations. Official Ielts Practice Materials. Cambridge: University of Cambridge ESOL Examinations, 2007.
MLA-referens (9:e uppl.)University of Cambridge ESOL Examinations. Official Ielts Practice Materials. University of Cambridge ESOL Examinations, 2007.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.