Cita APA (7a ed.)

Swan, M., & Walter, C. (1997). How english works: A grammar practice book. Oxford University Press.

Cita Chicago Style (17a ed.)

Swan, Michael, y Catherine Walter. How English Works: A Grammar Practice Book. Oxford; Buenos Aires: Oxford University Press, 1997.

Cita MLA (8a ed.)

Swan, Michael, y Catherine Walter. How English Works: A Grammar Practice Book. Oxford University Press, 1997.