Cita APA (7a ed.)

Soars, J., & Soars, L. (1993). Headway upper-intermediate. Oxford University Press.

Cita Chicago Style (17a ed.)

Soars, John, y Liz Soars. Headway Upper-intermediate. Oxford: Oxford University Press, 1993.

Cita MLA (8a ed.)

Soars, John, y Liz Soars. Headway Upper-intermediate. Oxford University Press, 1993.