Παραπομπή σε μορφή APA (7η εκδ.)

Scott L. Lun & Scott D. David. (2006). Natural English. Pre-Intermediate Workbook With Key: Workbook With Key. New York, Oxford University Press, 2006.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Scott L. Lun και Scott D. David. Natural English. Pre-Intermediate Workbook With Key: Workbook With Key. New York, Oxford University Press, 2006, 2006.

Παραπομπή σε μορφή MLA (9th εκδ.)

Scott L. Lun και Scott D. David. Natural English. Pre-Intermediate Workbook With Key: Workbook With Key. New York, Oxford University Press, 2006, 2006.