Cita APA (7a ed.)

Bowler, B., & Cunningham, S. (1991). Headway upper-intermediate: Pronunciation. Oxford University Press.

Cita Chicago Style (17a ed.)

Bowler, Bill, y Sarah Cunningham. Headway Upper-intermediate: Pronunciation. Oxford: Oxford University Press, 1991.

Cita MLA (8a ed.)

Bowler, Bill, y Sarah Cunningham. Headway Upper-intermediate: Pronunciation. Oxford University Press, 1991.