[Cha et al. 2007] Cha, M., Kwak, H., Rodriguez, P., Ahn, Y. and Moon, S.: "I tube, you tube, everybody tubes: analyzing the world's largest user generated content video system"; Proceedings of the 7th ACM SIGCOMM conference on Internet measurement, ACM New York, NY, USA (2007), 1--14.

[Hayes and Avesani 2007] Hayes, C. and Avesani, P.: "Using Blog Tags To Identify Topic Authorities", 'tag based clustering may not be adapted for this kind of distribution [power law]' (2007).

[Hayes et al. 2006] Hayes, C., Avesani, P. and Veeramachaneni, S.: "An analysis of the use of tags in a blog recommender system"; ITC-IRST Technical Report. http://sra. itc. it/people/hayes/pubs/06/hayes-ijcai07-tech-report. pdf  (2006).