(2006). English Skills.
Trích dẫn kiểu ChicagoEnglish Skills. 2006.
MLA引文English Skills. 2006.
警告：这些引文格式不一定是100％准确.
APA引文
(2006). English Skills.
Trích dẫn kiểu ChicagoEnglish Skills. 2006.
MLA引文English Skills. 2006.