Soars, J., & Soars, L. (2009). New Headway: Upper-Intermediate : Student's Book (New Edition.). Oxford University Press.

Soars, John, and Liz Soars. New Headway: Upper-Intermediate : Student's Book. New Edition. New York: Oxford University Press, 2009.

Soars, John, and Liz Soars. New Headway: Upper-Intermediate : Student's Book. New Edition. Oxford University Press, 2009.