1. Bailey, K. (1994). Typologies and taxonomies—An introduction to classification techniques. London: Sage Publications.
2. Bandura, A. (1997). Self-efficacy: The Exercise of Control. New York: W.H. Freeman.
3. Breidbach, St. (2003). Plurilingualism, Democratic Citizenship in Europe and the Role of English. Strasbourg: Council of Europe.
4. Commission of the European Communities (1995). White Paper on Education and Training. Teaching and Learning. Towards the Learning Society. Brussels:;1; CoEC.
5. Commission of the European Communities (2oo7). European Reference Framework for Key Competences for Lifelong Learning. Luxembourg: Office for Official Publications of the European Communities.