Thomson and Martinet. Practical English Grammar (4th.). Oxford University Press.
Cita Chicago (17th ed.)Thomson and Martinet. Practical English Grammar. 4th. New Delhi New Delhi: Oxford University Press.
Cita MLA (9th ed.)Thomson and Martinet. Practical English Grammar. 4th. Oxford University Press.
Atenció: Aquestes cites poden no estar 100% correctes.