1. Andreou, G. & Anastasiou, F. (n.d.). Vocabulary interaction among the three languages of trilingual children.
http://www.enl.auth.gr/symposium19/19thpapers/010_Andreou_Anastasiou.pdf
,
2. Baker, C., & Jones, S. P. (1998). Encyclopedia of bilingualism and bilingual education. Clevedon: Multilingual Matters.
3. Bialystok, E. (2001). Bilingualism in development. Cambridge: Cambridge University Press.
4. Bleyle, S. (2001). Learning English as a third language. Research Paper.
http://www.academia.edu/961210/Learning_English_as_a_Third_Language
5. Cambell, R., & Sais, E. (1995). Accelerated metalinguistic (phonological) awareness in bilingual children. British Journal of Developmental Psychology, 13, 61–68.