1. Capper, J. (2001). The emerging market for online learning: insights from the corporate sector, European Journal of Education, 36(2), 237-245.
2. Chen, T. (2003). Recommendations for creating and maintaining effective networked learning communities: a review of the literature, International Journal of Instructional Media, 30(1), 35-44.
3. CREL (2010). Exploring the Uncanny Valley. Center of Research in Entertainment and Learning in the UCSD Division of the California Institute for Telecommunications and Information Technology. Retrieved 2012 June 7, from: http://crel.calit2.net/.
4. Duyff, R.L. (1999). The value of lifelong learning: key element in professional career development. Journal of Am Diet Assoc. 99 (5), 538-543.
5. Edwards, R. (1997). Changing places? Flexibility, lifelong learning and a learning society. London, Routledge publishing.