Cita APA

Ur, P., & Ur, P. (1988). Grammar practice activities: A practical guide for teachers. Cambridge: Cambridge University Press.

Citación estilo Chicago

Ur, Penny, y Penny Ur. Grammar Practice Activities: A Practical Guide for Teachers. Cambridge: Cambridge University Press, 1988.

Cita MLA

Ur, Penny, y Penny Ur. Grammar Practice Activities: A Practical Guide for Teachers. Cambridge: Cambridge University Press, 1988.