Ward, A. (1994). Open doors: Workbook 2. Oxford: Oxford University press.
Trích dẫn kiểu ChicagoWard, Ann. Open Doors: Workbook 2. Oxford: Oxford University press, 1994.
MLA引文Ward, Ann. Open Doors: Workbook 2. Oxford: Oxford University press, 1994.
警告：这些引文格式不一定是100％准确.