Cita APA (7a ed.)

Gude K. Kathy & Duckworth M. Michael. (2003). Proficiency Masterclass: Student's Book (3-rd ed.). New York, Oxford University Press, 2003.

Cita Chicago Style (17a ed.)

Gude K. Kathy y Duckworth M. Michael. Proficiency Masterclass: Student's Book. 3-rd ed. New York, Oxford University Press, 2003, 2003.

Cita MLA (9a ed.)

Gude K. Kathy y Duckworth M. Michael. Proficiency Masterclass: Student's Book. 3-rd ed. New York, Oxford University Press, 2003, 2003.