Cita APA

Walker, E., & Elsworth, S. (2000). Grammar practice for upper intermediate students. England: Longman.

Chicago Style Citation

Walker, Elaine., i Steve Elsworth. Grammar Practice for Upper Intermediate Students. England: Longman, 2000.

Cita MLA

Walker, Elaine., i Steve Elsworth. Grammar Practice for Upper Intermediate Students. England: Longman, 2000.

Atenció: Aquestes cites poden no estar 100% correctes.