Cha, M., Kwak, H., Rodriguez, P., Ahn, Y.Y., Moon, S., {I tube, you tube, everybody tubes: analyzing the world's largest user generated content video system} (2007), S. 1--14.

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

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