1. All roads lead to “Philosophy”. (n.d.). Retrieved June 10, 2011, from http://www.xefer.com/
2. Bieber, M., Im, I., Rice, R. E., Goldman-Segall, R., Paul, R., & Stohr, E. A. … Turoff, M. (2002). Towards knowledge-sharing and learning in virtual professional communities. In Proceedings of the HICSS 2002 (p. 213).
3. Downes, S. (2006). PLE diagram. Retrieved June 10, 2011, from www.halfanhour.blogspot.com/2006/10/ple-diagram.html
4. Edtechpost. (2008-2009). A collection of PLE diagrams. Retrieved June 10, 2011, from www.edtechpost.wikispaces.com
5. Educause (2009). 7 things you should know about Personal Learning Environments, Retrieved June 10, 2011, from http://www.educause.edu/Resources/7ThingsYouShouldKnowAboutPerso/171521