T. Anderson, and J. Dron. Handbook of Research on Social Software and Developing Community Ontologies, page 1-17. Information Science Reference, (2009)
H. Ebner, and M. Palmér. Proceedings of the First International Workshop on Mashup Personal Learning Environments (MUPPLE08), 388. Maastricht, The Netherlands, Septiembre 2008., page 14-17. (2008)
C. Ullrich, K. Borau, H. Luo, X. Tan, L. Shen, and R. Shen. WWW '08: Proceeding of the 17th international conference on World Wide Web, page 705--714. New York, NY, USA, ACM, (2008)