Conrad, S., Biber, D., & Leech, G. N. (2002). Longman student grammar of spoken and written english: Workbook. Pearson Education.
Cita Chicago (17th ed.)Conrad, Susan, Douglas Biber, i Geoffrey N. Leech. Longman Student Grammar of Spoken and Written English: Workbook. Essex: Pearson Education, 2002.
Cita MLA (9th ed.)Conrad, Susan, et al. Longman Student Grammar of Spoken and Written English: Workbook. Pearson Education, 2002.
Atenció: Aquestes cites poden no estar 100% correctes.