THOMPSON, A., & MARTINET, A. (1981). A practical english grammar: Exercises 2.-- Ed.2. ELBS and Oxford University.

THOMPSON, A.J, and A.V MARTINET. A Practical English Grammar: Exercises 2.-- Ed.2. London: ELBS and Oxford University, 1981.

THOMPSON, A.J, and A.V MARTINET. A Practical English Grammar: Exercises 2.-- Ed.2. ELBS and Oxford University, 1981.