Richards, J. C., Hull, J., & Proctor, S. (1994). Changes: English for international communication : student's book 1. Cambridge: Cambridge University Press.
Dyfyniad Arddull ChicagoRichards, Jack C., Jonathan Hull, và Susan Proctor. Changes: English for International Communication : Student's Book 1. Cambridge: Cambridge University Press, 1994.
Dyfyniad MLARichards, Jack C., Jonathan Hull, và Susan Proctor. Changes: English for International Communication : Student's Book 1. Cambridge: Cambridge University Press, 1994.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.