1. Allen, V.F. (1983). Techniques in teaching vocabulary. New York: Oxford University Press.
2. Barcroft, J. (2002). Semantic and structural elaboration in L2 lexical acquisition. Language Learning, 52(2), 323-363.
3. Barcroft, J. (2004). Effects of sentence writing in second language lexical acquisition. Second Language Research, 20(4), 303-334.
4. Barzgar, G. (2009). The effect of semantic elaboration strategy on the retention of vocabulary among EFL Iranian students. Unpublished master's thesis, Islamic Azad University, Garmsar, Iran.
5. Beaton, A., Gruneberg, M., & Ellis, N. (1995). Retention of foreign vocabulary learned using the keyword method: A ten-year follow-up. Second Language Research, 11(2), 112-120.