Thomson, A., & Martinet, A. (1986). A Practical English grammar: Exercises (3rd ed.). Oxford University Press.

Thomson, A.J, and A.V Martinet. A Practical English Grammar: Exercises. 3rd ed. Oxford: Oxford University Press, 1986.

Thomson, A.J, and A.V Martinet. A Practical English Grammar: Exercises. 3rd ed. Oxford University Press, 1986.