Soars, J., & Soars, L. (1989). Headway advanced: Student's Book. New York: Oxford University Press.
Dyfyniad Arddull ChicagoSoars, John, và Liz Soars. Headway Advanced: Student's Book. New York: Oxford University Press, 1989.
Dyfyniad MLASoars, John, và Liz Soars. Headway Advanced: Student's Book. New York: Oxford University Press, 1989.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.