Richards, J. C., Hull, J., & Proctor, S. (1990). Interchange: English for international communication. Workbook 1. Cambridge University.
Cita Chicago Style (17a ed.)Richards, Jack C., Jonathan Hull, y Susan Proctor. Interchange: English for International Communication. Workbook 1. Cambridge: Cambridge University, 1990.
Cita MLA (9a ed.)Richards, Jack C., et al. Interchange: English for International Communication. Workbook 1. Cambridge University, 1990.
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