References :

Hardisty, David, and Scott Windeatt. 1989. CALL. Oxford, UK: Oxford University Press.

Higgins, John. 1991. "Fuel for learning: The neglected element of textbooks and CALL". CAELL Journal 2, 2:3-7.

Johns, Tim. 1988. "Whence and whither classroom concordancing?" In Bongaerts, Theo et al. (Eds.). Computer applications in language learning. Foris.

Stevens, Vance. 1991. "Classroom concordancing: Vocabulary materials derived from relevant, authentic text". English for Specific Purposes Journal 10: 35-46.

Stevens, Vance. 1995. "Concordancing with Language Learners: Why? When? What?" CAELL Journal, vol 6 #2, pp. 2-10.http://www.ruf.rice.edu/~barlo/stevens.html

Tribble, Chris. 1990. "Concordancing and an EAP writing programme". CAELL Journal 1, 2:10-15.

Wells, G. 1999. "Dialogic inquiry: Towards a sociocultural practice and theory of education". New York: Cambridge University Press. Chapter 10: The zone of proximal development and its implications for learning and teaching. http://www.oise.utoronto.ca/~gwells/resources/ZPD.html