Richards, J. C., Hull, J., & Proctor, S. (1994). Changes: English for international communication : student's book 1. Cambridge: Cambridge University Press.
استشهاد بنمط شيكاغوRichards, Jack C., Jonathan Hull, و Susan Proctor. Changes: English for International Communication : Student's Book 1. Cambridge: Cambridge University Press, 1994.
MLA استشهادRichards, Jack C., Jonathan Hull, و Susan Proctor. Changes: English for International Communication : Student's Book 1. Cambridge: Cambridge University Press, 1994.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.