1. Brown, H. D. (2000). Principles of Language Learning and Teaching. (4th ed.). White Plains, NY: Longman.
2. Baker, C. (2000). A Parent and Teacher's Guide to Bilingualism. (2nd ed.). Clevedon: Multicultural Matters Ltd.
3. Bialystok, E. (2001). Bilingualism in development: Language, literacy, and cognition. Cambridge: Cambridge University Press.
4. Blondin, C., Candelier, M., Edelenbos, P. Johnstone, R., Kubanek-German, A., & Taeschner, T. (1998). Foreign Languages in Primary and Pre-School Education: Context and Outcomes. A review of Recent Research within the European Union. London: CILT.
5. Bruce, T. (1997). Early childhood education. London: Hodder and Stoughton.