(1998). English in focus level B workbook.
Trích dẫn kiểu ChicagoEnglish in Focus Level B Workbook. 1998.
MLA引文English in Focus Level B Workbook. 1998.
警告：這些引文格式不一定是100％准確.
APA引文
(1998). English in focus level B workbook.
Trích dẫn kiểu ChicagoEnglish in Focus Level B Workbook. 1998.
MLA引文English in Focus Level B Workbook. 1998.