Cita APA (7th ed.)

Ur, P., & Swan, M. (2009). Grammar Practice Activities. A practical guide for teachers (Second edition.). Cambridge University Press.

Cita Chicago (17th ed.)

Ur, Penny, i Michael Swan. Grammar Practice Activities. A Practical Guide for Teachers. Second edition. Cambridge, United Kingdom: Cambridge University Press, 2009.

Cita MLA (9th ed.)

Ur, Penny, i Michael Swan. Grammar Practice Activities. A Practical Guide for Teachers. Second edition. Cambridge University Press, 2009.