Cita APA (7a ed.)

Ur, P. (1991). Grammar practice activities: A practical guide for teachers. Cambridge University Press.

Cita Chicago Style (17a ed.)

Ur, Penny. Grammar Practice Activities: A Practical Guide for Teachers. Cambridge: Cambridge University Press, 1991.

Cita MLA (8a ed.)

Ur, Penny. Grammar Practice Activities: A Practical Guide for Teachers. Cambridge University Press, 1991.