Cita APA (7a ed.)

Gairns R. Ruth & Redman S. Stuart. (2005). Natural English. Pre-intermediate: Class Audio CDs. New York, Oxford University Press, 2005.

Cita Chicago Style (17a ed.)

Gairns R. Ruth y Redman S. Stuart. Natural English. Pre-intermediate: Class Audio CDs. New York, Oxford University Press, 2005, 2005.

Cita MLA (9a ed.)

Gairns R. Ruth y Redman S. Stuart. Natural English. Pre-intermediate: Class Audio CDs. New York, Oxford University Press, 2005, 2005.