May, P. (1999). Knockout first certificate: Student's book (5th ed.). Oxford: Oxford University Press.
Dyfyniad Arddull ChicagoMay, Peter. Knockout First Certificate: Student's Book. 5th ed. Oxford: Oxford University Press, 1999.
Dyfyniad MLAMay, Peter. Knockout First Certificate: Student's Book. 5th ed. Oxford: Oxford University Press, 1999.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.