Scott L. Lun & Scott D. David. (2006). Natural English. Pre-Intermediate Workbook With Key: Workbook With Key. New York, Oxford University Press, 2006.
Chicago Style (17th ed.) CitationScott L. Lun and Scott D. David. Natural English. Pre-Intermediate Workbook With Key: Workbook With Key. New York, Oxford University Press, 2006, 2006.
MLA (9th ed.) CitationScott L. Lun and Scott D. David. Natural English. Pre-Intermediate Workbook With Key: Workbook With Key. New York, Oxford University Press, 2006, 2006.
Warning: These citations may not always be 100% accurate.