Rybold, G., & Harvey-Smith, N. (2013). Speaking, listening and understanding: English language debate for non-native speakers (Revised edition.). International Debate Education Association.

Rybold, Gary, and Neill Harvey-Smith. Speaking, Listening and Understanding: English Language Debate for Non-native Speakers. Revised edition. New York: International Debate Education Association, 2013.

Rybold, Gary, and Neill Harvey-Smith. Speaking, Listening and Understanding: English Language Debate for Non-native Speakers. Revised edition. International Debate Education Association, 2013.